Shipbuilding&Repair Quality Standard

Shipbuilding and Repair Quality Standard

Part A Shipbuilding and Repair Quality Standard for New Construction

Part B Repair Quality Standard for Existing Ships

Appendix - Referenced IACS Unified Requirements

IACS Rec. 1996

No. 47

47-1

No.47(1996)

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Part A Shipbuilding andRepair Quality Standard forNew Construction___________________________________________________________________________

PART A - SHIPBUILDING AND REPAIR QUALITY STANDARDS FOR NEW CONSTRUCTION

1. Scope2. General requirements for new construction3. Qualification of personnel and procedures3.1 Qualification of welders3.2 Approval of welding procedures3.3 Qualification of NDE operators4. Materials4.1 Materials for structural members4.2 Under thickness tolerances4.3 Surface conditions5. Cutting5.1 Gas cutting5.2 Plasma arc cutting5.3 Laser beam cutting6. Fabrication and fairness6.1 Flange longitudinals and flange brackets6.2 Built-up sections6.3 Corrugated bulkheads6.4 Pillars, brackets and stiffeners6.5 Maximum heating temperature on surface for line heating6.6 Block assembly6.7 Special sub-assembly6.8 Shape6.9 Fairness of plating between frames6.10 Fairness of plating with frames7. Alignment8. Welding8.1 Typical butt weld plate edge preparation (manual welding)8.2 Typical fillet weld plate edge preparation (manual welding)8.3 Typical butt and fillet weld profile (manual welding)8.4 Lap, plug and slot welding8.5 Distance between welds8.6 Automatic welding9. Repair9.1 Typical misalignment repair9.2 Typical butt weld plate edge preparation repair (manual welding)9.3 Typical fillet weld plate edge preparation repair (manual welding)9.4 Typical fillet and butt weld profile repair (manual welding)9.5 Distance between welds repair9.6 Erroneous hole repair9.7 Repair by insert plate9.8 Weld surface repair

REFERENCES1. IACS “Bulk Carriers - Guidelines for Surveys, Assessment and Repair of Hull Structure”2. TSCF “Guidelines for the inspection and maintenance of double hull tanker structures”3. TSCF “Guidance manual for the inspection and condition assessment of tanker structures”4. IACS UR W7 “Hull and machinery steel forgings”5. IACS UR W8 “Hull and machinery steel castings”6. IACS UR W11 “Normal and higher strength hull structural steel”7. IACS UR W13 “Allowable under thickness tolerances of steel plates and wide flats”8. IACS UR W14 “Steel plates and wide flats with improved through thickness properties”9. IACS UR W17 “Approval of consummables for welding normal and higher strength hull structural steels”10. IACS UR Z10.1 “Hull surveys of oil tankers”and Z10.2 “Hull surveys of bulk carriers” Annex I11. IACS Recommendation No. 12 “Guidelines for surface finish of hot rolled plates and wide flats “13. IACS Recommendation No. 20 “ Guide for inspection of ship hull welds”

1. Scope

1.1 This standard provides guidance on shipbuilding quality standards for the hull structure during newconstruction and the repair standard where the quality standard is not met.

Whereas the standard generally applies to- conventional ship types,- parts of hull covered by the rules of the Classification Society,- hull structures constructed from normal and higher strength hull structural steel,

the applicability of the standard is in each case to be agreed upon by the Classification Society.

The standard does generally not apply to the new construction of- special types of ships as e.g. gas tankers- structures fabricated from stainless steel or other, special types or grades of steel

1.2 The standard covers typical construction methods and gives guidance on quality standards for the mostimportant aspects of such construction. Unless explicitly stated elsewhere in the standard, the level ofworkmanship reflected herein will in principle be acceptable for primary and secondary structure of conventionaldesigns. A more stringent standard may however be required for critical and highly stressed areas of the hull, andthis is to be agreed with the Classification Society in each case. In assessing the criticality of hull structure andstructural components, reference is made to ref. 1, 2 and 3.

1.3 Details relevant to structures or fabrication procedures not covered by this standard are to be approved by theClassification Society on the basis of procedure qualifications and/or recognised national standards.

1.4 It is intended that these standards provide guidance where established shipbuilding or national standardsapproved by the Classification Society do not exist.

1.5 For use of this standard, fabrication fit-ups, deflections and similar quality attributes are intended to beuniformly distributed about the nominal values. The shipyard is to take corrective action to improve workprocesses that produce measurements where a skewed distribution is evident. Relying upon remedial steps thattruncate a skewed distribution of the quality attribute is unacceptable.

2. General requirements for new construction

2.1 In general, the work is to be carried out in accordance with the Classification Society Rules and under thesupervision of the Surveyor to the Classification Society

2.2 Provisions are to be made for proper accessibility, staging, lighting and ventilation. Welding operations are tobe carried out under shelter from rain, snow and wind.

2.3 Welding of hull structures is to be carried out by qualified welders, according to approved and qualifiedwelding procedures and with welding consumables approved by the Classification Society, see Section 3. Weldingoperations are to be carried out under proper supervision by the shipbuilder.

3. Qualification of personnel and procedures

3.1 Qualification of welders

3.1.1 Welders are to be qualified in accordance with the procedures of the Classification Society or to a recognisednational or international standard, e.g. EN 287, ISO 9606, ASME Section IX, ANSI/AWS D1.1. Recognition ofother standards is subject to submission to the Classification Society for evaluation. Subcontractors are to keeprecords of welders qualification and, when required, furnish valid approval test certificates.

3.1.2 Welding operators using fully mechanised or fully automatic processes need generally not pass approvaltesting provided that the production welds made by the operators are of the required quality. However, operatorsare to receive adequate training in setting or programming and operating the equipment Records of training andproduction test results shall be maintained on individual operator’s files and records, and be made available to theClassification Society for inspection when requested.

3.2 Qualification of welding procedures

Welding procedures are to be qualified in accordance with the procedures of the Classification Society or arecognised national or international standard, e.g. EN288, ISO 9956, ASME Section IX, ANSI/AWS D1.1.Recognition of other standards is subject to submission to the Classification Society for evaluation. The weldingprocedure should be supported by a welding procedure qualification record. The specification is to include thewelding process, types of electrodes, weld shape, edge preparation, welding techniques and positions.

3.3 Qualification of NDE operators

3.3.1 Personnel performing non-destructive examination for the purpose of assessing quality of welds inconnection with new construction covered by this standard, are to be qualified in accordance with ClassificationSociety rules or to a recognised international or national qualification scheme. Records of operators and theircurrent certificates are to be kept and made available to the Surveyor for inspection.

4. Materials

4.1 Materials for Structural Members

All materials, including weld consummables, to be used for the structural members are to be approved by theClassification Society as per the approved construction drawings and meet the respective IACS UnifiedRequirements. Additional recommendations are contained in the following paragraphs.

All materials used should be manufactured at a works approved by the Classification Society for the type andgrade supplied.

4.2 Under Thickness Tolerances

The maximum permissible under thickness tolerance, for hull structural plates and wide flats with thicknesses of5mm and over, for both normal and high strength steels, is -0.3mm. The thickness is to be measured at randomlocations whose distance from an edge shall be at least 10mm. Local surface depressions resulting fromimperfections and ground areas resulting from the elimination of defects may be disregarded provided theimperfections or grinding are in accordance with the requirements of Section 4.3 “Surface Conditions”.

4.3 Surface Conditions

4.3.1 Definitions

Minor Imperfections: pittings, rolled-in scale, indentations, roll marks, scratches and grooves

Defects: Cracks, shells, sand patches, sharp edged seams and minor imperfections not exceeding the limits of table 1 in case that the sum of the influenced area exceeds 5% of the total surface in question

Depth of Imperfections or defects: the depth is to be measured from the surface of the product

4.3.2 Unrepaired Conditions

Minor imperfections, in accordance with the limits described in Table 1, are permissible and may be leftunrepaired.

4.3.3 Repairs of Defects

Defects are to be repaired by grinding or welding irrespective of their size and number. Repair by grinding maybe carried out over the entire surface up to a depth equal to the under thickness tolerances given in para.4.2.

The sum of the repairs by welding and of the repairs by grinding, reducing the nominal thickness by more than0.3mm, shall not exceed 2% of the total surface in question.

4.3.4 Repairs by Grinding

For ground areas with a thickness less than the minimum permissible thickness stated in para.4.2, the nominalthickness is not to be reduced by more than 7% or 3mm, whichever is the lesser. Each single ground area is notto exceed 0.25m2.

The defects are to be completely removed by grinding. Complete elimination of the defects is to be verified by amagnetic particle or dye penetrant test procedure. The ground areas must have smooth transitions to thesurrounding surface.

4.3.5 Repairs by welding

Local defects, which cannot be repaired by grinding, may be repaired by chipping and/or grinding followed bywelding in accordance with the qualified procedures approved by the Classification Society concerned.

Any single welded area is not to exceed 0.125m2. The weld preparation should not reduce the thickness of theproduct below 80% of the nominal thickness. Welding is to be completed with one layer of weld bead in excess,which is subsequently to be ground smooth, level with the plate surface. The soundness of the repair is to beverified by ultrasonic, magnetic particle or dye penetrant methods.

Plate Thickness SurfaceArea

100% 15% 5% 2%

3 ≤ t < 8mm N + 0.1 0.2 - 0.4 -N 0.2 - 0.3 0.4N - 0.1 0.2 - - 0.4N - 0.2 0.1 0.2 - 0.4N - 0.3 0.0 0.2 - 0.4

8 ≤ t < 25mm N + 0.2 0.3 - 0.5 -N + 0.1 0.3 - 0.4 0.5N 0.3 - - 0.5N - 0.1 0.2 0.3 - 0.5N - 0.2 0.1 0.3 - 0.5N - 0.3 0.0 0.3 - 0.5

25 ≤ t <40mm N + 0.3 0.4 - 0.6 -N + 0.2 0.4 - 0.5 0.6N + 0.1 0.4 - - 0.6N 0.3 0.4 - 0.6N - 0.1 0.2 0.4 - 0.6N - 0.2 0.1 0.4 - 0.6N - 0.3 0.0 0.4 - 0.6

40 ≤ t <80mm N + 0.5 0.5 - 0.8 -N + 0.4 0.5 - 0.7 0.8N + 0.3 0.5 - 0.6 0.8N + 0.2 0.5 - - 0.8N + 0.1 0.4 0.5 - 0.8N 0.3 0.5 - 0.8N - 0.1 0.2 0.5 - 0.8N - 0.2 0.1 0.5 - 0.8N - 0.3 0.0 0.5 - 0.8

80 ≤ t<150mm N + 0.6 0.6 - 0.9 -N + 0.5 0.6 - 0.8 0.9N + 0.4 0.6 - 0.7 0.9N + 0.3 0.6 - - 0.9N + 0.2 0.5 0.6 - 0.9N + 0.1 0.4 0.6 - 0.9N 0.3 0.6 - 0.9N - 0.1 0.2 0.6 - 0.9N - 0.2 0.1 0.6 - 0.9N - 0.3 0.0 0.6 - 0.9

N - Nominal Plate Thickness

Table 1 Limits for minor imperfections left unrepaired

4.3.6 Further Defects

4.3.6.1 Lamination

Investigation to be carried out at the steelmill into the cause and extent of the laminations. Severe lamination is tobe repaired by a local insert plates. The minimum breadth of the plate to be repaired by insert is to be: • 1600mm for shell and strength deck plating in way of cruciform or T-joints,• 800mm for shell, strength deck plating and other primary members,• 300mm for other structural members.

Local limited lamination may be repaired by chipping and/or grinding followed by welding in accordance withsketch (a). In case where the local limited lamination is near the plate surface, the repair may be carried out asshown in sketch (b). For limitations see paragraph 4.3.5.

(a) (b)

4.3.6.2 Weld Spatters

Loose weld spatters are to be removed completely by grinding to clean metal (see Table 9.13) on:

• shell plating• deck plating on exposed decks• in tanks for chemical cargoes• in tanks for fresh water and for drinking water• in tanks for lubricating oil, hydraulic oil, including service tanks

5. Cutting

5.1 Gas Cutting

The deviation u of cut edges (see sketch (a)), from a right angle or from a required slope, and the roughness ofthe cut edges R, is to meet the following requirements:

Mechanised Gas Cutting Manual Gas Cutting: Free Edges

Cut Thickness Standard Limit Strength Members Standard Limit

a≤20mm u=0.6mm u=1.2mm u=1.5mm u=1.5mmR=100µm R=150µm R=150µm R=300µm

Others

a>20mm u=0.75mm u=1.5mm u=1.5mm u=1.5mmR-100µm R=150µm R=300µm R=500µm

Manual Gas Cutting: Welding Edges

Standard Limit

Strength Members u=1.5mm u=1.5mmR=400µm R=800µm*

Others u=1.5mm u=1.5mmR=800µm* R=1500µm*

Individual non-sharp notches caused by torch failures (scouring) are not to be greater than 3mm in depth. Deeperscores should be removed by grinding.

* Unless the welding procedure needs smaller tolerances.

a

u

u

a

(a) deviation u from a right angle or from a required slope

5.2 Plasma Arc Cutting

The deviation u of the cut edge (see sketch (a)), from a right angle or from a required slope, and the roughness ofthe cut edge R, is to meet the following requirements:

Mechanised Plasma Arc Cutting

Cut Thickness Standard Limit

a≤20mm u=1.0mm u=1.5mmR=100µm R=150µm

a>20mm u=0.75mm u=1.5mmR=100µm R=150µm

The tolerances for manual cutting are to be agreed by the Classification Society concerned.

5.3 Laser Beam Cutting

The standard range and the tolerance limits for the deviation from a right angle or from a required slope of thecut edges and the roughness of the cut edges are to be agreed by the Classification Society concerned.

6. Fabrication and fairness

6.1 Flanged longitudinals and flanged brackets (see Table 6.1)6.2 Built-up sections (see Table 6.2)6.3 Corrugated bulkheads (see Table 6.3)6.4 Pillars, brackets and stiffeners (see Table 6.4)6.5 Maximum heating temperature on surface for line heating (see Table 6.5)6.6 Block assembly (see Table 6.6)6.7 Special sub-assembly (see Table 6.7)6.8 Shape (see Table 6.8 and 6.9)6.9 Fairness of plating between frames (see Table 6.10)6.10 Fairness of plating with frames (see Table 6.11)

7. Alignment

The quality standards for alignment of hull structural components during new construction are shown in Tables7.1, 7.2 and 7.3. The classification society may require a closer construction tolerance in areas requiring specialattention, as follows: • Regions exposed to high stress concentrations• Fatigue prone areas• Detail design block erection joints• • Higher tensile steel regions

8. Welding Details

8.1 Typical butt weld plate edge preparation (manual welding) - see Table 8.1 and 8.28.2 Typical fillet weld plate edge preparation (manual welding) - see Table 8.3 and 8.48.3 Typical butt and fillet weld profile (manual welding) - see Table 8.58.4 Lap, plug and slot welding - see Table 8.68.5 Distance between welds - see Table 8.78.6 Automatic welding - see Table 8.8

9. Repair

9.1 Typical misalignment repair - see Tables 9.1 to 9.39.2 Typical butt weld plate edge preparation repair (manual welding) - see Table 9.4 and 9.59.3 Typical fillet weld plate edge preparation repair (manual welding) - see Tables 9.6 to 9.89.4 Typical fillet and butt weld profile repair (manual welding) - see Table 9.99.5 Distance between welds repair - see Table 9.109.6 Erroneous hole repair - see Table 9.119.7 Repair by insert plate - see Table 9.129.8 Weld surface repair - see Table 9.13

Detail Standard Limit Remarks

b

a

compared to correct size

+ 3 mm + 5 mm

TABLE 6.1 - FLANGED LONGITUDINALS AND BRACKETS

+ 3 mm + 5 mm per 100 mm of a

Angle between flange and web

compared to template

Straightness in plane of flangeand web

+ 10 mm + 25 mm per 10 m

a

Breadth of flange


Frames and longitudinal

+ 1.5 mm + 3 mm per 100 mm of a

Distortion of face plate

d

d < 3 + a/100 mm d < 5 + a/100 mm

Distortion of girder and transverseat upper edge and flange

+5 mm +8 mm per span betweenprimary members

TABLE 6.2 - BUILT UP SECTIONS

a

a


Mechanical bending

R > 3t mm

Breadth of corrugation

Depth of corrugation

+ 3 mm + 6 mm

+ 3 mm + 6 mm

h

P P

Pitch and depth of swedgedcorrugated bulkhead comparedwith correct value

TABLE 6.3 - CORRUGATED BULKHEADS

h : + 2.5 mm h : + 5 mm

Where it is not aligned with other bulkheads

P : + 6 mm P : + 9 mm

Where it is aligned with other bulkheads

P : + 2 mm P : + 3 mm

Breadth of corugation web

+ 3 mm + 6 mm

Material to be suitable forcold flanging (forming)and welding in way ofradius

R

t


4 mm 6 mm

Pillar (between decks)

D

Cylindrical structure diameter(pillars, masts, posts, etc.)

+ D/200 mm + D/150 mm

max. + 5 mm max. 7.5 mm

Tripping bracket and small stiffener,distortion at the part of free edge

a < t/2 mm

at

HD

F

θ0

Snipe end of secondary face platesand stiffeners θ0 = 300

H = 15 mm

D = 25 mm

F = 15 mm

+ 5 mm- 5 mm

+ 10 mm- 5 mm

+ 5 mm

TABLE 6.4 - PILLARS, BRACKETS AND STIFFENERS

max. 8mm

TABLE 6.5 - MAXIMUM HEATING TEMPERATURE ON SURFACE FOR LINE HEATING FOR PLATE FORMING

Item Standard Limit Remarks

ConventionalProcessAH32-EH32 &AH36-EH36

Water cooling justafter heating

under 650°C

TCMP typeAH32-EH32 &AH36-EH36(Ceq.>0.38%)

Air cooling afterheating

under 900°C

Air cooling andsubsequent watercooling afterheating

under 900°C (startingtemperature of watercooling to be under500°C)

TMCP typeAH32-DH32 &AH36-DH36(Ceq.≤0.38%)

Water cooling justafter heating or aircooling

under 1000°C

TMCP typeEH32 & EH36(Ceq.≤0.38%)

Water cooling justafter heating or aircooling

under 900°C

NOTE:

Ceq = C + Mn

6 +

Cr + Mo + V

5 +

Ni + Cu

15 (%)

TABLE 6.6 - BLOCK ASSEMBLY


Flat Plate Assembly

Length and Breadth ±2.5mm ±5mm

Distortion ±10mm ±20mm

Squareness ±5mm ±10mm

Deviation of interior members from plate 5mm 10mm

Curved plate assembly

Length and Breadth ±2.5mm ±5mm Measured along

Distortion ±10mm ±20mm the girth



Flat cubic assembly

Length and Breadth ±2.5m ±5mm

Distortion ±10mm ±20mm



Twist ±10mm ±20mm

Deviation between upper and lower plate ±5mm ±10mm

Curved cubic assembly

Length and Breadth ±2.5mm ±5mm measured along

Distortion ±10mm ±20mm with girth



Twist ±15mm ±25mm

Deviation between upper and lower plate ±7mm ±15mm

TABLE 6.7 - SPECIAL SUB-ASSEMBLY


Distance between upper/lower gudgeon ±5mm ±10mm

Distance between aft edge of boss and aftpeak bulkhead

±5mm ±10mm

Twist of sub-assembly of stern frame 5mm 10mm

Deviation of rudder from shaft centre line 4mm 8mm

Twist of rudder plate 6mm 10mm

Flatness of top plate of main engine bed 5mm 10mm

Breadth and length of top plate of mainengine bed

±4mm 6mm


TABLE 6.8 - SHAPE

CL

Rise of floor amidships

Cocking-up of aft-body

Cocking-up of fore body

Deformation for the distance betweentwo adjacent bulkheads

Deformation for the whole length

+ 50 mm

+ 15 mm

+ 30 mm

+ 20 mm

+ 15 mm

per 100 m againstthe line of keelsighting

TABLE 6.9 - SHAPE


Length between perpendiculars ±50per 100m

Applied toships of 100metre lengthand above.For theconvenience ofthemeasurementthe point wherethe keel isconnected tothe curve of thestern may besubstituted forthe foreperpendicularin themeasurementof the length.

Length between aft edge of boss andmain engine

±25mm

Moulded breadth at midship ±15mm Applied toships of 15metre breadthand above.Measured onthe upper deck.

Moulded depth at midship ±10mm Applied toships of 10metre depthand above.

TABLE 6.10 - FAIRNESS OF PLATING BETWEEN FRAMES


Shell plateParallel part(side & bottom shell)

4mm

Fore and aft part 5mm

Tank top plate 4mm 8mm

BulkheadLongl. bulkheadTrans. bulkheadSwash bulkhead 6mm

Parallel part 4mm

Strength deck Fore and aft part 6mm 9mm

Covered part 7mm 9mm

Second deckBare part 6mm 8mm


Forecastle deckpoop deck

Bare part 4mm 8mm


Super structuredeck

Bare part 4mm 6mm


Outside wall 4mm 6mm

House wall Inside wall 6mm 8mm


Interior member (web of girder, etc) 5mm 7mm

Floor and girder in double bottom 5mm 7mm

s

d

d

s

300 < s < 1000

TABLE 6.11 - FAIRNESS OF PLATING WITH FRAMES


Shell plate Parallel part ±2 /1000mm ±3 /1000mm

Fore and aft part ±3 /1000mm ±4 /1000mm

Strength deck(excludingcross deck) andtop plate ofdouble bottom

- ±3 /1000mm ±4 /1000mm To be measuredbetween on trans.space (min. l=3m)

Bulkhead - ±4 /1000mm ±5 /1000mm

Others - ±5 /1000mm ±6 /1000mm

l m

l = span of frame(minimum l = 3 m)

d


a < 3.0 mm

TABLE 7.1 - ALIGNMENT

a < 0.15t strengtha < 0.2t other

t

a

a

t

Alignment of fillet welds

Where t3 is less thant1, then t3 should besubsituted for t1 inthe standard

t1

t2

t3

a

a1

a

t1

θ0

a) strength and highertensile

a < t1/3 measuredon the median

a1 < (5t1 - 3t2)/6measured on theheel line

b) other


a1 < (2t1 - t2)/2measured on theheel line

t1 < t2


a) strength and highertensile steel


b) other

a1 < t1/2 measuredon the heel line

a1

Alignment of butt welds



Alignment of flange of T-longitudinal

a b

a < 0.04b strength a = 8.0 mm

a t

Alignment of height of T-bar,L-angle bar or bulb

Primary membersa < 0.15t

Secondary membersa < 0.20t

3.0 mm

d < L/50L

d

Alignment of panel stiffener

Alignment of lap welds

a

a

a < 2.0 mm

a

Gap between bracket/intercostal andstiffener

a < 2.0 mm 3 mm


d > 75 mm

s < 2.0 mm


d

Position of scallop

ss

Gap around stiffener cut-out

s

a

Gap between beam and frame

a < 2.0 mm


Square butt

G

t

θ0

G

t

R

Single bevel butt

G

t

R

θ0

Double bevel butt

G

t R

θ0

Double vee butt, uniform bevels

G

t

R

θ0

α0

h

Double vee butt, non-uniform bevel

TABLE 8.1 -TYPICAL BUTT WELD PLATE EDGE PREPARATION (MANUAL WELDING)

t < 5 mmG = 3 mm

t > 5 mmG < 3 mmR < 3 mmθ = 500 - 700

t > 19 mmG < 3 mmR < 3 mmθ = 500 - 700

G < 3 mmR < 3 mmθ = 500 - 700

G < 3 mmR < 3 mm6 < h < t/3 mmθ = 500

α = 900

see Note 1

see Note 1

see Note 1

see Note1

see Note 1

Different plate edge preparation may be accepted or approved by the Classification Society on the basisof an appropiate welding procedure specification.

NOTE 1

For welding procedures other that manual welding, see paragraph 3.2 Qualification of weld procedures


Single vee butt, one side welding withbacking strip (temporary or permanent)

G

t

θ0

TABLE 8.2 - TYPICAL BUTT WELD PLATE EDGE PREPARATION (MANUAL WELDING)

G = 3 - 9 mmθ = 300 - 450 see Note 1

Single vee butt

G

t

θ0

R

θ = 500 - 700

R < 3 mm

G < 3 mm

see Note 1


NOTE 1



G

t

Tee Fillet

TABLE 8.3 - TYPICAL FILLET WELD PLATE EDGE PREPARATION (MANUAL WELDING)

G < 2 mm

G

t

R

θ0

Single bevel tee

G < 3 mmR < 3 mmθ = 500

see Note 1

G

α0 β0

Small angle fillet

α = 500 - 700

β = 700 - 900

G < 2 mmsee Note 1

see Note 1

G

t

Single bevel tee with permanentbacking

G < 4 - 6 mm

Not normally forstrength members

also see Note 1

θo

θo = 30o - 450


NOTE 1


Detail Standard Remarks

G

t

G

t

R

θ0

rθ0

Single ’J’ tee

R

Double bevel tee symmetrical

TABLE 8.4 - TYPICAL FILLET WELD PLATE EDGE PREPARATION (MANUAL WELDING)

Limit

G = 2.5 - 4 mmr = 12 - 15 mmR = 3mmθ > 350

t > 19 mmG < 3 mmR < 3 mmθ = 500

G

t

rθ0

R

Double J bevel symmetrical

G = 2.5 - 4 mmR < 3 mmr = 12 - 15 mmθ > 350

see Note 1

G

t

R

500500

Double bevel tee assymetrical

t > 19 mmG < 3 mmR < 3 mm

see Note1

see Note 1

see Note 1


NOTE 1



S

a

450

Fillet weld leg length

θ0

Fillet weld toe angle

θ < 900

R

t θ0 h

θ < 60o

h < 0.2R

Butt weld toe angle

Butt weld undercut

D

Fillet weld undercut

TABLE 8.5 -TYPICAL BUTT AND FILLET WELD PROFILE (MANUAL WELDING)

s = leg lengtha = throat depth

s > 0.9sda > 0.9ad

sd = design s

ad = design a

maximumh 6 mm

over shortweld lengths

in areas of stressconcentration and fatigue,the Class Society mayrequire a lesser angle

D = 0 mm 0.5 mm

D = 0 mm 0.5 mmD


bt1

t2

t1 > t2

b = 2t2 + 25

Fillet weld in lap joint

bt2

b > 2t2 + 25 mm

Fillet weld in joggled lap joint

TABLE 8.6 -TYPICAL LAP, PLUG AND SLOT WELDING (MANUAL WELDING)

l L

Plug welding

t < 12 mm 12 < t < 25 mm

l 60 mm 80 mmR 6 mm 0.5t mm

t < 12 mm t > 12mm

G 20 mm 2tl 80 mm 100 mm

L 2l - 3l max. 250 mm

q 0

G

l L

tR

Slot welding

G

t1

t1 > t2

t

location of lap joint tobe approved by theClassification Society

q 40o-50o 30o

G 12mm t mm

L > 2l


Scallops over weld seams

d

Distance between two butt welds

d

Distance between butt weld andfillet weld

d > 10 mm

d > 0 mm

d

d

Distance between butt welds

TABLE 8.7 - DISTANCE BETWEEN WELDS

d > 5 mm

for r > 30 mm

for cut-outs

d > 30 mm

for margin plates

d > 300 mm

150 mm

r

d


G

G

G

Submerged Arc Welding (SAW)

0 < G < 0.8 mm G < 5 mm

TABLE 8.8 - AUTOMATIC ARC WELDING

Edge preparation as perTables 8.1 and 8.2

SAW may follow WPSapproved by theClassification Society

see Note 1

Detail Repair standard Remarks

t

a

Alignment of butt joints

a b

LAlignment of flange of T-longitudinal

a

Alignment of height of T-bar,L-angle bar or bulb

Alignment of lap welds

a

a

t1

t2

t3

t1 < t2


TABLE 9.1 - TYPICAL MISALIGNMENT REPAIR

a

Where t3 is lessthan t1, then t3should be substitutedfor t1 in standard

a) strength and higher tensile steel

t1/3 < a < t1/2 - generally increaseweld throat by 10%

a > t1/2 - release and adjust over a minimumof 50a

b) Other

Strength membersa > 0.15t1 or a > 3 mmrelease and adjust

Othersa > 0.2t1 or a > 3 mmrelease and adjust

2 mm < a < 5 mmweld leg length to be increased by the sameamount as increase in gap

a > 5 mmmembers to be re-aligned

When 0.04b < a < 0.08b, max. 8 mmgrind corners to smooth taper over aminimum distance L=3a

When a > 0.08b or 8 mmrelease and adjust over minimum L=50a

When 3 mm < a < 6 mmbuilding up by weldingWhen a > 6 mmrelease and adjust over minimum L=50afor primary structure and L=30a elsewhere

a > t1/2 - release and adjust over a minimumof 30a

L


TABLE 9.2 - TYPICAL MISALIGNMENT REPAIR

a

Gap between beam and frame

a > 2 mm - release and adjust

a

Gap between bracket/intercostal andstiffener

When 2 mm < a < 5 mmweld leg length to be increased byincrease in gap

When 5 mm < a < 10 mmchamfer 300 - 400 and build upwith welding

When a > 10 mmincrease gap to 50mm and fitcollar plate

b

b = (2t + 25) mm, min. 50 mm

t t1

t > t1


Position of scallop

TABLE 9.3 - MISALIGNMENT REPAIR

ss

Gap around stiffener cut-out

s

d

b (min. 50mm)

When d < 75 mm, web plate to becut between scallop and slot, andcollar plate to be fitted

When s > 10 mmcut off nib and fit collar plate withsame height as nib

b

20 mm < b < 50 mm

When 5 mm < s < 10 mmnib to be chamfered and built up bywelding

When 2 mm < s < 5 mmweld leg length to be increased as muchas increase in gap opening over 2 mm

OR fit smal collar over scallop

OR fit collar plate over scallop


Square butt

G

t

θ0

G

t

R

Single bevel butt

G

t

R

θ0

Double bevel butt

G

t R

θ0

Double vee butt, uniform bevels

G

t

R

θ0

α0

h

Double vee butt, non-uniform bevel

TABLE 9.4 - TYPICAL BUTT WELD PLATE EDGE PREPARATION REPAIR (MANUAL WELDING)

When G < 10 mmchamfer to 450 and build up bywelding

When G > 10 mmbuild up with backing strip; remove,back gouge and seal weld;or, insert plate, min. width 300 mm

When 3 mm < G < 3t/2 mm (maximum25mm)

build up gap with welding onone or both sides of preparation, withpossible use of backing strip asnecessary, to maximum t/2.

When G > 25 mm or 3t/2an insert plate, of minimum width300mm, to welded in place

300 mm

where a backing strip is used, the backing stripis to be removed, the weld back gouged, and asealing weld made

max. t/2

Detail Repair Standard Remarks

Single vee butt, one side weldingwith backing strip

G

t

θ0

G

t

θ0

Single vee butt, one side welding

Single vee butt

G

t

θ0

R

TABLE 9.5 - TYPICAL BUTT WELD PLATE EDGE PREPARATION REPAIR (MANUAL WELDING)

When G < 25 mm or G < t/2build up edge preparation on one orboth sides, grind edge preparation,weld with backing strip, removebacking strip, back gouge,

When G > 25 mminsert plate, min. width 300mm

300 mm

When 3 mm < G < 3t/2 mm (maximum25mm)

build up gap with welding onone or both sides of preparation, withpossible use of backing strip asnecessary, to maximum t/2.

When G > 25 mm or t/2an insert plate, of minimum width300mm, to welded in place

300 mm

Where a backing strip is used, the backingstrip is to be removed, the weld back gouged,and a sealing weld made

max. t/2

and back weld


G

t

Tee Fillet

G

t

300- 450

G

TABLE 9.6 - TYPICAL FILLET WELD PLATE EDGE PREPARATION REPAIR (MANUAL WELDING)

2 mm < G < 5 mm - leg lengthincreased to Rule leg + (G - 2)

5 mm < G < 16 mm - chamfer to300 to 450, build up with welding,on one side, with or without backingstrip, grind and weld

G > 16 mm or G > 1.5t - new plateto be inserted (min. 300mm)

300 mmminimum

t1

t

t2

a

b

Liner treatment

t2 < t < t1G < 2 mma = 5 mm + fillet leg length

Not to be used incargo area or areasof tensile stressperpendicular toliner


G

t

TABLE 9.7 - TYPICAL FILLET WELD PLATE EDGE PREPARATION REPAIR (MANUAL WELDING)

3 mm < G < 5 mmbuild up weld

G > 16 mm - new plate to beinserted of minimum width 300mm

5 mm < G < 16 mm - build up withwelding, with or without backingstrip, remove backing strip if used,back gouge and back weld

300 mmminimum

G

t

R

θ0

Single bevel tee


G

t

G

t

R

θ0

rθ0

Single ’J’ tee

R

Double bevel tee symmetrical

G

t

R

500500

Double bevel tee assymetrical

G

t

rθ0

R

Double J bevel symmetrical

TABLE 9.8 -TYPICAL FILLET WELD PLATE EDGE PREPARATION REPAIR (MANUAL WELDING)

When 3 mm < G < 16 mmbuild up with welding using ceramicor other approved backing bar,remove, back gouge and back weld

When G > 16 mm - insert plate ofminimum height 300mm to be fitted

300 mmmin.

as single bevel tee


S

a

450

Fillet weld leg length

Fillet weld toe angle

θ > 900 grinding, and welding,where necessary, to makeθ < 900

R

t θ0 h

Butt weld toe angle

D

Butt weld undercut

D

Fillet weld undercut

TABLE 9.9 - TYPICALFILLET AND BUTT WELD PROFILE REPAIR (MANUAL WELDING)

Where D > 1 mmundercut to be filled by welding

Increase leg or throat bywelding over

Short beads, less than50 mm, to be avoidedin higher tensile steel

θ > 900 grinding, and welding,where necessary, to makeθ < 900

Microgrooves of groundedge to be parallel to mainstress direction

Where 0.5 < D < 1 mmundercut to be ground smooth(localised only)

θ0


Scallops over weld seams

TABLE 9.10 - DISTANCE BETWEEN WELDS REPAIR

Hole to be cut and ground smooth toobtain distance


TABLE 9.11 - ERRONEOUS HOLE REPAIR

Holes made erroneously D < 200 mm

D

Strength membersopen hole to minimum 75 mm dia.,fit and weld spigot piece

θ0GD

l

t

t1

θ = 300 - 400

G = 4 - 6 mm1/2 t < t1 < tl = 50 mm

ORopen hole to over 300 mm and fitinsert plate

Other members

open hole to over 300 mm and fitinsert plateOR fit lap plate

t1

t2

L

t1 = t2 L = 50 mm, min

Holes made erroneously D > 200 mm

D

Strength membersopen hole to over 300 mm and fitinsert plate

Other membersopen hole to over 300 mm and fitinsert plateOR fit lap plate

t1

t2

L

t1 = t2 L = 50 mm, min

The fiting of spigot piecesin areas of high stressconcentration or fatigueis to be approved by theClassification Society

Fillet weld to be madeafter butt weld


TABLE 9.12 - REPAIR BY INSERT PLATE

B

L

Repair by insert plate

L = 300 mm minimum

B = 300 mm minimum

R = 5t mm100 mm minimum

(1) seam with insert piece is to bewelded first

(2) original seam is to be releasedand welded over for a minimumof 100 mm

B

L

(2)

(2)

(1)

(2)

(2)

(1)

R

(4) (4)

(3)

Lmin

(2) (1)

150 150

(4)

(3) (3)

Repair of built section by insert plate

Lmin > 300 mm

Welding sequence

(1) (2) (3) (4)

Web butt weld scallop to befilled during final pass (4)


TABLE 9.13 - WELD SURFACE REPAIR

Weld spatter 1. Remove spatter observed beforeblasting with scraper or chippinghammer, etc.

2. For spatter observed after blasting:

a) Remove with a chipping hammer,scraper, etc.

In principal, nogrinding is appliedto weld surface

h < 3 mm

Irregularity of manual weld

When the surface irregularity exceeds3mm, apply grinding until theirregularity becomes less than 3mm

This repair standardis applicable to filletwelds also

Arc strike

Remove the hardened zone by grinding

b) For spatter not easily removedwith a chipping hammer, scraper,etc., grind the sharp angle ofspatter to make it obtuse

___________________________________________________________________________

Part B Repair Quality Standardfor Existing Ships___________________________________________________________________________

PART B -SHIPBUILDING AND REPAIR QUALITY STANDARD FOR EXISTING SHIPS

CONTENTS:

1. Scope2. General requirements to repairs and repairers3. Qualification of personnel3.1 Qualification of welders3.2 Qualification of welding procedures3.3 Qualification of NDE operators4. Materials4.1 General requirements to materials4.2 Equivalency of material grades5. General requirements to welding5.1 Correlation of welding consumables to hull structural steels5.2 General requirements to preheating and drying out5.3 Dry welding on hull plating below the waterline of vessels afloat6. Repair quality standard6.1 Welding, general6.2 Renewal of plates6.3 Doubler on plates6.4 Renewal of internals/stiffeners6.5 Renewal of internals/stiffeners - transitions inverted angles/bulb profiles6.6 Termination of straps6.7 Welding of pitting corrosion6.8 Welding repairs of cracks6.9 Grinding of shallow cracks

REFERENCES

1. IACS “Bulk Carriers - Guidelines for Surveys, Assessment and Repair of Hull Structure”2. TSCF “Guidelines for the inspection and maintenance of double hull tanker structures”3. TSCF “Guidance manual for the inspection and condition assessment of tanker structures”4. IACS UR W 11 “Normal and higher strength hull structural steels”5. IACS UR W 13 “Allowable under thickness tolerances of steel plates and wide flats”6. IACS UR W 17 “Approval of consumables for welding normal and higher strength hull structural steels”7. IACS Z 10.1 “Hull surveys of oil tankers” and Z 10.2 “Hull surveys of bulk carriers” Table IV8. IACS UR Z 13 “Voyage repairs and maintenance”9. IACS Recommendation 12 “Guidelines for surface finish of hot rolled steel plates and wide flats”10. IACS Recommendation 20 “Guide for inspection of ship hull welds”

1. Scope

1.1 This standard provides guidance on quality of repair of hull structures. The standard covers permanentrepairs of existing ships.

Whereas the standard generally applies to- conventional ship types,- parts of hull covered by the rules of the Classification Society,- hull structures constructed from normal and higher strength hull structural steel, the applicability of the standard is in each case to be agreed upon by the Classification Society.

The standard does generally not apply to repair of- special types of ships as e.g. gas tankers- structures fabricated from stainless steel or other, special types or grades of steel

1.2 The standard covers typical repair methods and gives guidance on quality standard on the most importantaspects of such repairs. Unless explicitly stated elsewhere in the standard, the level of workmanship reflectedherein will in principle be acceptable for primary and secondary structure of conventional design. A morestringent standard may however be required for critical and highly stressed areas of the hull, and is to be agreedwith the Classification Society in each case. In assessing the criticality of hull structure and structuralcomponents, reference is made to ref. 1, 2 and 3.

1.3 Restoration of structure to the original standard may not constitute durable repairs of damages originatingfrom insufficient strength or inadequate detail design. In such cases strengthening or improvements beyond theoriginal design may be required. Such improvements are not covered by this standard, however it is referred toref. 1, 2 and 3.

2. General requirements for repairs and repairers

2.1 In general, when hull structure covered by classification is to be subjected to repairs, the work is to be carriedout under the supervision of the Surveyor to the Classification Society. Such repairs are to be agreed prior tocommencement of the work.

2.2 Repairs are to be carried out by workshops, repair yards or personnel who have demonstrated their capabilityto carry out hull repairs of adequate quality in accordance with the Classification Society’s requirements and thisstandard.

2.3 Repairs are to be carried out under working conditions that facilitate sound repairs. Provisions are to be madefor proper accessibility, staging, lighting and ventilation. Welding operations are to be carried out under shelterfrom rain, snow and wind.

2.4 Welding of hull structures is to be carried out by qualified welders, according to approved and qualifiedwelding procedures and with welding consumables approved by the Classification Society, see Section 3. Weldingoperations are to be carried out under proper supervision of the repair yard.

2.5 Where repairs to hull which affect or may affect classification are intended to be carried out during a voyage,complete repair procedure including the extent and sequence of repair is to be submitted to and agreed upon bythe Surveyor to the Classification Society reasonably in advance of the repairs. See Ref. 8.

3. Qualification of personnel

3.1 Qualification of welders3.1.1 Welders are to be qualified in accordance with the procedures of the Classification Society or to a recognisednational or international standard, e.g. EN 287, ISO 9606, ASME Section IX, ANSI/AWS D1.1. Recognition ofother standards is subject to submission to the Classification Society for evaluation. Repair yards and workshopsare to keep records of welders qualification and, when required, furnish valid approval test certificates.

3.1.2 Welding operators using fully mechanised of fully automatic processes need generally not pass approvaltesting, provided that production welds made by the operators are of the required quality. However, operators areto receive adequate training in setting or programming and operating the equipment. Records of training andproduction test results shall be maintained on individual operator’s files and records, and be made available to theClassification Society for inspection when requested.

3.2 Qualification of welding proceduresWelding procedures are to be qualified in accordance with the procedures of the Classification Society or arecognised national or international standard, e.g. EN288, ISO 9956, ASME Section IX, ANSI/AWS D1.1.Recognition of other standards is subject to submission to the Classification Society for evaluation. The weldingprocedure should be supported by a welding procedure qualification record. The specification is to include thewelding process, types of electrodes, weld shape, edge preparation, welding techniques and positions

3.3 Qualification of NDE operators3.3.1 Personnel performing non destructive examination for the purpose of assessing quality of welds inconnection with repairs covered by this standard, are to be qualified in accordance with the Classification Societyrules or to a recognised international or national qualification scheme. Records of operators and their currentcertificates are to be kept and made available to the Surveyor for inspection.

4. Materials

4.1. General requirements for materials4.1.1 The requirements for materials used in repairs are in general the same as the requirements for materialsspecified in the Classification Society’s rules for new constructions, (ref. 5)

4.1.2 Replacement material is in general to be of the same grade as the original approved material. Alternatively,material grades complying with recognised national or international standards may be accepted by theClassification Societies provided such standards give equivalence to the requirements of the original grade or areagreed by the Classification Society. For assessment of equivalency between steel grades, the general requirementsand guidelines in Section 4.2 apply.

4.1.3 Higher tensile steel is not to be replaced by steel of a lesser strength unless specially approved by theClassification Society.

4.1.4 Normal and higher strength hull structural steels are to be manufactured at works approved by theClassification Society for the type and grade being supplied.

4.1.5 Materials used in repairs are to be certified by the Classification Society applying the procedures andrequirements in the rules for new constructions. In special cases, and normally limited to small quantities,materials may be accepted on the basis of alternative procedures for verification of the material’s properties. Suchprocedures are subject to agreement by the Classification Society in each separate case.

4.2. Equivalency of material grades

4.2.1 Assessment of equivalency between material grades should at least include the following aspects;- heat treatment/delivery condition- chemical composition- mechanical properties- tolerances

4.2.2 When assessing the equivalence between grades of normal or higher strength hull structural steels up toand including grade E40 in thickness limited to 50 mm, the general requirements in Table 4.1 apply.

4.2.3 Guidance on selection of steel grades to certain recognised standards equivalent to hull structural steelgrades specified in Classification Societies’ rules is given in Table 4.2

5. General requirements to welding

5.1 Correlation of welding consumables with hull structural steels

5.1.1 For the different hull structural steel grades welding consummables are to be selected in accordance withIACS UR W17 (see Ref.5).

5.2 General requirements to preheating and drying out

5.2.1 The need for preheating is to be determined based on the chemical composition of the materials, weldingprocess and procedure and degree of joint restraint.

5.2.2 A minimum preheat of 50o C is to be applied when ambient temperature is below 0°C. Dryness of thewelding zone is in all cases to be ensured.

5.2.3 Guidance on recommended minimum preheating temperature for higher strength steel is given in Table 5.1.For automatic welding processes utilising higher heat input e.g. submerged arc welding, the temperatures may bereduced by 50o C. For re-welding or repair of welds, the stipulated values are to be increased by 25 o C.

Items to beconsidered

Requirements Comments

Chemicalcomposition

- C; equal or lower- P and S; equal or lower- Mn; approximately the same but not exceeding 1.6%- Fine grain elements; in same amount- Deoxidation practice

The sum of the elements, e.g. Cu, Ni, Cr and Moshould not exceed 0.8%

Mechanicalproperties

- Tensile strength; equal or higher- Yield strength; equal or higher- Elongation; equal or higher- Impact energy; equal or higher at same or lower temperature, whereapplicable

Actual yield strength should not exceedClassification Society Rule minimumrequirements by more than 80 N/mm2

Condition ofsupply

Same or better Heat treatment in increasing order;- as rolled (AR)- controlled rolled (CR)- normalised (N)- thermo-mechanically rolled (TM)1)

- quenched and tempered (QT)1)

1) TM- and QT-steels are not suitable for hot forming

Tolerances - Same or stricter Permissible under thickness tolerances;- plates: 0.3 mm- sections: according to recognised standards

Table 4.1 Minimum extent and requirements to assessment of equivalency between normal or higherstrength hull structural steel grades

5.3 Dry welding on hull plating below the waterline of vessels afloat

5.3.1. Welding on hull plating below the waterline of vessels afloat is acceptable only on normal and higherstrength steels with specified yield strength not exceeding 355 MPa and only for local repairs. Welding involvingother high strength steels or more extensive repairs against water backing is subject to special consideration andapproval by the Classification Society of the welding procedure.

5.3.2. Low-hydrogen electrodes or welding processes are to be used when welding on hull plating against waterbacking. Coated low-hydrogen electrodes used for manual metal arc welding should be properly conditioned toensure a minimum of moisture content.

5.3.3 In order to ensure dryness and to reduce the cooling rate, the structure is to be preheated by a torch orsimilar prior to welding, to a temperature of minimum 5oC or as specified in the welding procedure.

Table 4.2 Guidance on steel grades comparable to the normal and high strength hull structural steel grades given in Classification Society rules

Steel grades according to Classification Societies’ rules (ref. 5) Comparable steel grades

Yieldstress

Tensilestrength

Elongation Average impactenergy

ISO630-80

EN ASTM JIS

Grade ReH

min.N/mm2

Rm

N/mm2

A5

min.%

Temp.

°C

J, min.

L T

4950/2/31981

EN 10025-93EN 10113-93

A 131 G 3106

ABDE

235 400 - 502 22

+200-20-40

- -27 2027 2027 20

Fe 360BFe 360CFe 360D-

S235JRG2S235J0S235J2G3S275NL/ML

ABDE

SM41BSM41B(SM41C)-

A 27D 27E 27

265 400 - 530 220-20-40

27 20Fe 430CFe 430D-

S275J0G3S275N/MS275NL/ML

---

---

A 32D 32E 32 315 440 - 590 22

0-20-40 31 22

---

---

AH32DH32EH32

SM50B(SM50C)-

A 36D 36E 36 355 490 - 620 21

0-20-40 34 24

Fe 510CFe 510DE355E

S355N/MS355N/MS355NL/ML

AH36DH36EH36

SM53B(SM53C)-

A 40D 40E 40 390 510 - 650 20

0-20-40 41 27

E390CCE390DDE390E

S420N/MS420N/MS420NL/ML

AH40DH40EH40

(SM58)--

Note : In selecting comparable steels from this table, attention should be given to the requirements of Table 4.1 and the dimension requirements of the product with respectto Classification Society rules.

Carbon equivalent Recommended minimum preheat temperature ( 0 C )1) tcomb ≤ 50 mm 2) 50 mm<tcomb ≤ 70 mm 2) tcomb >70 mm 2)

Ceq ≤ 0.39 - - 50Ceq ≤ 0.41 - - 75Ceq ≤ 0.43 - 50 100Ceq ≤ 0.45 50 100 125Ceq ≤ 0.47 100 125 150Ceq ≤ 0.50 125 150 175

Table 5.1 Preheating temperature

NOTES

1) Ceq = C + Mn

6 +

Cr + Mo + V

5 +

Ni + Cu

15 (%)

2) Combined thickness tcomb = t1 + t2 + t3 + t4 , see figure

= =

t1 t2 t1t2

t3

t4

6. Repair quality standard

6.1 Welding, general

d

d

Fig. 6.1 Groove roughness

NOTE :Slag, grease, loose mill scale, rust and paint, other than primer, to be removed.

Item Standard Limit RemarksMaterial Grade Same as original or

higherSee Section 4

Welding Consumables IACS UR-W17(ref. 6)

Approval according. toequivalentinternational standard

Groove / roughness See note and Fig. 6.1 d < 1.5 mm Grind smooth

Pre-Heating See Table 5.1 Steel temperature notlower than 5oC

Welding with water onthe outside

See Section 5.3 Acceptable for normaland high strengthsteels

-Moisture to be removed by a heating torch

Alignment As for newconstruction

Weld finish IACS guide forinspection of ship hullwelds (ref. 10)

NDE IACS guide (ref. 10) At random with extentto be agreed withattending surveyors

6.2 Renewal of plates

3

21

4

14

32

100mm 100mm

R

R = 5 x plate thicknessmin. 100mm

Fig 6.2 Welding sequence for inserts

Item Standard Limit RemarksSize insert Min. 300x300mm

R = 5 x thicknessCircular inserts:Dmin=200mm

Min. 200x200mmMin R = 100 mm

Material grade Same as original orhigher

See Section 4.

Edge Preparation As for newconstruction

In case of noncompliance increasethe amount of NDE

Welding sequence See fig.6.2Weld sequence is1→ 2 → 3 → 4

For primary memberssequence 1 and 2transverse to the mainstress direction



NDE IACS guide (ref. 10)

6.3 Doublers on plating

Local doublers are normally only allowed as temporary repairs, except as original compensation for openings, within the main hull structure.

R

Pitch

Size ofslot

ld

t

Slot weld throat

Fig. 6.3 Doublers on plates

Item Standard Limit RemarksExisting plating General: t > 5 mm For areas where

existing plating is lessthan 5mm plating apermanent repair byinsert is to be carriedout.

Extent/size Rounded off corners. min 300x300mmR > 50mm

Thickness of doubler (td) td ≤ tp (tp = originalthickness of existingplating )

td > tp/3

Material grade Same as original plate See Section 4

Edge preparation As for [newbuilding]new construction

Doublers welded onprimary strengthmembers: (Le: leglength)when t > Le + 5mm,the edge to be tapered(1:4)

Welding As for [newbuilding]new construction

Welding sequencesimilar to insert plates.

Weld size(throat thickness) Circumferencial and inslots: 0.6 x td

Slot welding Normal size of slot:(80-100) x 2 td

Distance from doubleredge and between slots:d < 15 td

Max pitch betweenslots 200mm

dmax = 500mm

For doubler extendedover several supportingelements, see figure 6.3

NDE IACSRecommendation 20( Ref. 10)

6.4 Renewal of internals/stiffeners

12

3

dd

Min. size of insert

Release fillet weld overa distance d prior towelding sector 3

Fig 6.4 Welding sequence for inserts of stiffeners

Item Standard Limit RemarksSize insert Min. 300 mm Min. 200mm

Material grade Same as original orhigher

See Section 4.

Edge Preparation As for newconstruction.Fillet weld stiffenerweb/plate to be releasedover min. d = 150 mm

Welding sequence See fig.6.4 .Weld sequence is1→ 2 → 3



NDE IACS guide (ref. 10)

6.5 Renewal of internals/stiffeners - transitions inverted angle/bulb profile

The application of the transition is allowed for secondary structural elements.

b1

b2

tf

tf2

15o

1:4

bf

1:4

l

==

t1

t2

h1

h2

15o

Transition angle

Fig. 6.5 Transition between inverted angle and bulb profile

Item Standard Limit Remarks(h1 - h2) < 0.25 x b1

| t1 - t2| 2 mm Without taperingtransition.

Transition angle 15 degrees At any arbitrary section

Flanges tf = tf2bf = bf2

Length of flatbar 4 x h1

Material See Section 4.

6.6 Termination of straps

Rb

Taper /b > 3

Strap

Assymmetrical arrangement

Symmetrical arrangement

Increased throatthickness

Taper /b > 3bStrap t

t

Increased throatthickness

Fig. 6.6 Termination of straps

Item Standard Limit RemarksTapering /b > 3 Special consideration

to be drawn to designof strap terminations in

Radius 0.1 x b min 30mm fatigue sensitive areas.Material See paragraph 2.0

General requirement tomaterials.

Weld size Depending on numberand function of straps.Throat thickness to beincreased 15 % towardends.

Welding Welding sequencefrom middle towardsthe free ends

See sketch. Forwelding of lengths >1000mm step weldingto be applied.

6.7 Welding of pitting corrosion

NOTES:Shallow pits may be filled by applying coating or pit filler. Pits can be defined as shallow when their depth is lessthan 1/3 of the orginal plate thickness.

Grind flushStart outside pitFinish outside pit

Welding direction

Fig. 6.7 Welding of pits

Reference is made to TSCF Guidelines, Ref. 2 & 3.

Item Standard Limit RemarksExtent/depth Pits/grooves are to be

welded flush with theoriginal surface.

If deep pits or groovesare clustered togetheror remaining thicknessis less than 6 mm, theplate should berenewed.

See also IACSRecommendation 12( Ref.9)

Cleaning Heavy rust to beremoved

Pre-Heating See Table 5.1 Required whenambienttemperature < 5oC

Always use propanetorch or similar toremove any moisture

Welding sequence Reverse direction foreach layer

See also IACS guideno. 12


NDE IACS guide (ref. 10) Min. 10% extent Preferably MPI

6. 8 Welding repairs for cracks

Tab

A

Fig. 6.8.a Step back technique Fig 6.8.b End crack termination

1

Fig 6.8.c Welding sequence for cracks with length less than 300 mm

Fig. 6.8.d Groove preparation(U-groove left and V-groove right)

3 2 1

3 2 1

θo

R

Item Standard Limit RemarksGroove preparation θ=45-60o

r= 5 mmFor through plate cracks asfor newbuilding. Else seefig 6.9.d

Termination Termination to haveslope 1:3

For cracks ending on edgesweld to be terminated on atab see Fig 6.9.b

Extent On plate max. 400 mmlength. Vee out 50 mmpast end of crack

On plate max 500mm. Linear crack,not branched

Welding sequence See fig 6.9.c forsequence and direction

For cracks longerthan 300 mm step-back techniqueshould be used Fig6.9.a

Always use low hydrogenwelding consumables


NDE IACS guide (ref.10) 100 % MP or PE ofgroove

100 % surface crackdetection + UE or RE forbutt joints

6.9 Grinding of shallow cracks

Disk grinder Rotary burr grinder

Max. grindingdepth

Final grinding direction

Main stress direction

+

Fig 6.9 Grinding

Item Standard Limit RemarksExtent For short cracks only

max. 4 tt = Plate thickness

Max. length100 mm

See also IACSrecommendation 12,(ref. 9)

Grinding direction Final grindingmicrogrooves parallelto main stress direction

Grinding always to befinished by a rotatingburr and not a diskgrinder

Grinding depth Max. 0.2 tt = Plate thickness

Always smoothtransition

NDE IACS guide forinspection of ship hullwelds (ref. 10)

100 % MPI

___________________________________________________________________________

Appendix - Referenced IACSUnified Requirements___________________________________________________________________________

APPENDIX - REFERENCED IACS UNIFIED REQUIREMENTS

CONTENTS

IACS UR W7 “Hull and machinery steel forgings”IACS UR W8 “Hull and machinery steel castings”IACS UR W11 “Normal and higher strength hull structural steel”IACS UR W13 “Allowable under thickness tolerances of steel plates and wide flats”IACS UR W14 “Steel plates and wide flats with improved through thickness properties”IACS UR W17 “Approval of consumables for welding normal and higher strength hull structural steels”IACS UR Z10.1 “Survey of oil tankers”and Z10.2 “Survey of Bulk Carriers” Annex IIACS UR Z13 “Voyage repairs and maintenance”IACS Recommendation 12 “Guidelines for surface finish of hot rolled steel plates and wide flats”IACS Recommendation 20 “Guide for inspection of ship hull welds”

W7

Hull and machinery steel forgings

W7.1 Scope(1978)

W7.1.1 All important steel forgings, as defined in the relevant construction Rules, are to bemanufactured and tested in accordance with the requirements of the following paragraphs. Theserequirements are also applicable to rolled slabs and billets used as a substitute for forgings and to rolledbars used for the manufacture (by machining operations only) of shafts, bolts, studs and othercomponents of simple shape.

W7.1.2 These requirements are applicable only to steel forgings where the design and acceptance testsare related to mechanical properties at ambient temperature. For other applications, additionalrequirements may be necessary especially when the forgings are intended for service at low or elevatedtemperatures.

W7.1.3 Alternatively, forgings which comply with national or proprietary specifications may beaccepted provided such specifications give reasonable equivalence to these requirements or are otherwisespecially approved or required by the Classification Society.

W7.1.4 Where small and identical forgings are produced in large quantities the manufacture may adoptalternative procedures for testing and inspection subject to the approval of the Classification Society.

W7.2 Manufacture(1978)

W7.2.1 All important forgings are to be made at works where the manufacturer has demonstrated to thesatisfaction of the Classification Society that the necessary manufacturing and testing facilities areavailable and are supervised by qualified personnel. A programme of approval tests may be required inaccordance with the procedures of individual Societies.

W7.2.2 The steel used in the manufacture of forgings is to be made by the open hearth, electric or basicoxygen process or by other processes approved by the Classification Society.

W7(1978)

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W7.2.3 Adequate top and bottom discards are to be made to ensure freedom from piping and harmfulsegregations in the finished forgings.

W7.2.4 The plastic deformation is to be such as to ensure soundness, uniformity of structure andsatisfactory mechanical properties after heat treatment. For components where the fibre deformation ismainly longitudinal, the total reduction ratio is generally to be in accordance with Table 1.

Table 1

W7.2.5 Where disc type forgings such as gear wheels are made by upsetting, the thickness of any partof the disc is to be not more than one half of the length of the billet from which it was formed providedthat this billet has received an initial forging reduction of not less than 1,5:1. Where the piece used hasbeen cut directly from an ingot or where the billet has received an initial reduction of less than 1,5:1, thethickness of any part of the disc is to be not more than one third of the length of the original piece.

W7.2.6 Rings and other types of hollow forgings are to be made from pieces cut from ingots or billetsand which have been suitably punched, bored or trepanned prior to expanding or drawing on a suitablemandrel. Alternatively, pieces from hollow cast iron ingots may be used. The wall thickness of theforging is to be not more than one half of the thickness of the prepared hollow piece from which it wasformed. Where this is not practicable the forging procedure is to be such as to ensure that adequate workis given to the piece prior to punching, etc. This may be either longitudinal or upset working of not lessthan 2:1.

W7.2.7 For certain components, where grain flow is required in the most favourable direction havingregard to the mode of stressing in service, the proposed method of manufacture may require specialapproval by the Classification Society. In such cases, tests may be required to demonstrate that asatisfactory structure and grain flow are obtained.

W7.2.8 The shaping of forgings or rolled slabs and billets by flame cutting, scarfing or arc-air gougingis to be undertaken in accordance with recognized good practice and, unless otherwise approved, is to becarried out before the final heat treatment. Preheating is to be employed when necessitated by thecomposition and/or thickness of the steel.For certain components, subsequent machining of all flame cut surfaces may be required.

W7.2.9 When two or more forgings are joined by welding to form a composite component, details ofthe proposed procedure are to be submitted for approval. Welding procedure tests may be required.

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W7.2.3

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NOTES

1. L and D are the length and diameter respectively of the part of the forging under consideration.

2. The reduction ratio is to be calculated with reference to the average cross-sectional area of the ingot. Where an ingot is initially upset, this reference area may be taken as the average cross-sectional area after this operation.

3. For rolled bars used as a substitute for forgings (see W7.1.1) the reduction ratio is to be not less than 6:1.

TotalMethod of manufacture reduction ratio

Made directly from ingots or from forged 3:1 where L>Dblooms or billets 1,5:1 where L≤D

Made from rolled products 4:1 where L>D2:1 where L≤D

W7.3

W7.3 Quality of forgings(1978)

W7.3.1 All forgings are to be free from surface or internal defects which would be prejudicial to theirproper application in service.

W7.4 Chemical composition(1978)

W7.4.1 All forgings are to be made from killed steel and the chemical composition is to be appropriatefor the type of steel, dimensions and required mechanical properties of the forgings being manufactured.

W7.4.2 Details of the proposed chemical composition for alloy steel forgings are to be submitted forapproval.

W7.4.3 For carbon and carbon-manganese steel forgings the chemical composition of ladle samples isto comply with the following overall limits:

Carbon 0,60% max.Silicon 0,45% max.Manganese 0,30/1,50%Sulphur 0,040% max.Phosphorus 0,040% max.

Residual elements:Copper 0,30% max.Chromium 0,30% max.Molybdenum 0,15% max.Nickel 0,40% max.

W7.4.4 For alloy steel forgings the chemical composition of ladle samples is to include the content ofall alloying elements and is to comply with the following overall limits and the requirements of theapproved specifications:

Carbon 0,45% max.Silicon 0,45% max.Sulphur 0,035% max.Phosphorus 0,035% max.

W7.4.5 At the option of the manufacturer, suitable grain refining elements such as aluminium, niobiumor vanadium may be added. The content of such elements is to be reported in the ladle analysis.

W7.4.6 Where steel forgings are intended for welded construction the proposed chemical compositionis subject to approval by the Classification Society.

W7.5 Heat treatment (including surface hardening and straightening)(1978)

W7.5.1 At an appropriate stage of manufacture, after completion of all hot working operations, forgingsare to be suitably heat treated to refine the grain structure and to obtain the required mechanicalproperties.

W7.5.2 Except as provided in W5.5.7 and W5.5.8 forgings are to be supplied in one of the followingconditions:(a) Carbon and carbon-manganese steels Fully annealed

NormalizedNormalized and temperedQuenched and tempered

(b) Alloy steels Quenched and temperedFor all types of steel the tempering temperature is to be not less than 550°C.

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W7.5.3 Alternatively, alloy steel forgings may be supplied in the normalized and tempered condition, inwhich case the specified mechanical properties are to be agreed with the Classification Society.

W7.5.4 Heat treatment is to be carried out in properly constructed furnaces which are efficientlymaintained and have adequate means for control and recording of temperature. The furnace dimensionsare to be such as to allow the whole forging to be uniformly heated to the necessary temperature. In thecase of very large forgings alternative methods of heat treatment will be specially considered by theClassification Society.

W7.5.5 If for any reasons a forging is subsequently heated for further hot working the forging is to bere-heat treated.

W7.5.6 Where it is intended to surface harden forgings, full details of the proposed procedure andspecification are to be submitted for the approval of the Classification Society. For the purposes of thisapproval, the manufacture may be required to demonstrate by test that the proposed procedure gives auniform surface layer of the required hardness and depth and that it does not impair the soundness andproperties of the steel.

W7.5.7 Where induction hardening or nitriding is to be carried out after machining, forgings are to beheat treated at an appropriate stage to a condition suitable for this subsequent surface hardening.

W7.5.8 Where carburizing is to be carried out after machining forgings are to be heat treated at anappropriate stage (generally either by full annealing or by normalizing and tempering) to a conditionsuitable for subsequent machining and carburizing.

W7.5.9 If any straightening operation is performed after the final heat treatment consideration shouldbe given to a subsequent stress relieving heat treatment in order to avoid the possibility of harmfulresidual stresses.

W7.6 Mechanical tests(1978)

W7.6.1 Test material, sufficient for the required tests and for possible re-test purposes, is to be providedwith a cross-sectional area of not less than that part of the forging which it represents. This test materialis to be integral with each forging except as provided in W7.6.7 and W7.6.10.

W7.6.2 For the purpose of these requirements a set of tests is to consist of one tensile test specimenand, when required, three impact test specimens. When impact tests are required, either Charpy V-notchor Charpy U-notch test specimens may be used at the option of the manufacturer, unless otherwisespecified by the Classification Society.

W7.6.3 Test specimens are to be cut with their axes either mainly parallel (longitudinal test) or mainlyperpendicular (transverse test) to the principal direction of fibre deformation.

W7.6.4 The location of the axes of test specimens with regard to the distance below the surface of theforging is to be in accordance with the requirements of individual Classification Societies.

W7.6.5 Except as provided in W7.6.10 the number and direction of tests is to be as follows.

(a) Hull components such as rudderstocks, pintles etc. General machinery components such as shafting, connecting rods, etc.One set of tests is to be taken from the end of each forging in a longitudinal direction except that, at the discretion of the manufacture and if agreed by the Surveyor, the alternative directions or positions as shown in Fig. 1, 2 and 3 may be used. Where a forging exceeds both 4 tonnes in mass and 3m in length one set of tests is to be taken from each end. These limits refer to the 'as forged' mass and length but excluding the test material.

W7.5.3

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W7.6

(b) PinionsWhere the finished machined diameter of the toothed portion exceeds 200mm one set of tests is to be taken from each forging in a transverse direction adjacent to the toothed portion (test position B in Fig. 4). Where the dimensions preclude the preparation of tests from this position, tests in a transverse direction are to be taken from the end of the journal (test position C in Fig. 4). If however, the journal diameter is 200mm or less the tests are to be taken in a longitudinal direction (test position A in Fig. 4). Where the finished length of the toothed portion exceed 1,25m, one set of tests is to be taken from each end.

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Test position B (transverse)

Test position A (longitudinal)

Fig. 1 Plain shaft

Test position C (transverse)


Fig. 2 Flanged shaft

Test position B (longitudinal)

(through bolt hole)

Test position D (transverse)

Fig. 3 Flanged shaft with collar


Test position C (transverse) Test position B

(longitudinal)

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W7.6

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Test position C (transverse)

Fig. 4 Pinion



L

D d


L = length of toothed portion D = diameter of toothed portion d = jornal diameter

��

Test Position A (transverse)


Fig. 5 Gear wheel

��Test Position A (equivalent to longitudinal, see W7.6.3)

Test position B (equivalent to longitudinal, see W7.6.3)

Fig. 6 Gear rim (made by expanding)

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(c) Small pinionsWhere the finished diameter of the toothed portion is 200mm or less one set of tests is to be taken in a longitudinal direction (test position A in Fig. 4).

(d) Gear wheelsOne set of tests is to be taken from each forging in a transverse direction (test position A or B in Fig. 5).

(e) Gear wheel rims (made by expanding)One set of tests is to be taken from each forging (test position A or B in Fig. 6). Where the finished diameter exceeds 2,5m or the mass (as heat treated by excluding test material) exceeds 3 tonnes, two sets of tests are to be taken from diametrically opposite positions (test positions A and B in Fig. 6).

(f) Pinion sleevesOne set of tests is to be taken from each forging in a transverse direction (test position A or B in Fig. 7). Where the finished length exceeds 1,25m one set of tests is to be taken from each end.

(g) CrankwebsOne set of tests is to be taken from each forging in a transverse direction.

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��Fig. 7 Pinion sleeve

Test position A (transverse)



Test position C (transverse) Coupling end

Fig. 8 Solid forged crankshaft

Test position B (longitudinal)

(h) Solid forged crankshaftsOne set of tests is to be taken in a longitudinal direction from the coupling end of each forging (test position A in Fig. 8).Where the mass (as heat treated but excluding test material) exceeds 3 tonnes tests in a longitudinal direction are to be taken from each end (test positions A and B in Fig. 8). Where, however, the crankthrows are formed by machining or flame cutting, the second set of tests is to be taken in a transverse direction from material removed from the crankthrow at the end opposite to the coupling (test position C in Fig. 8).

W7.6.6 For combined web and pin crankshaft forgings and other forgings where the method ofmanufacture has been specially approved in accordance with W7.2.7, the number and position of testspecimens is to be agreed with the Classification Society having regard to the method of manufactureemployed.

W7.6.7 When a forging is subsequently divided into a number of components, all of which are heattreated together in the same furnace charge, for test purposes this may be regarded as one forging and thenumber of tests required is to be related to the total length and mass of the original multiple forging.

W7.6.8 Except for components which are to be carburized or as otherwise specially agreed, testmaterial is not to be cut from a forging until all heat treatment has been completed.

W7.6.9 When forgings are to be carburized after machining, sufficient test material is to be provided forboth preliminary tests at the forge and for final tests after completion of carburizing.For this purpose duplicate sets of test material are to be taken from positions as detailed in W7.6.5,except that irrespective of the dimensions or mass of the forging, tests are required from one positiononly and, in the case of forgings with integral journals, are to be cut in a longitudinal direction.This test material is to be machined to a diameter of D/4 or 60mm, whichever is less, where D is thefinished diameter of the toothed portion.For preliminary tests at the forge one set of test material is to be given a blank carburizing and heattreatment cycle simulating that which subsequently will be applied to the forging.For final acceptance tests, the second set of test material is to be blank carburized and heat treated alongwith the forgings which they represent.At the discretion of the forgemaster or gear manufacture test samples of larger cross section may beeither carburized or blank carburized, but these are to be machined to the required diameter prior to thefinal quenching and stress relieving heat treatment.Alternative procedures for testing of forgings which are to be carburized may be specially agreed withthe Classification Society.

W7.6.10 Where a number of small forgings of about the same size are made from one cast and heattreated in the same furnace charge, batch testing procedures may be adopted using one of the forgings fortest purposes or alternatively using separately forged test samples. These test samples are to have areduction ratio similar to that used for the forgings which they represent. They are to be properlyidentified and heat treated along with the forgings. In such cases at least one set of tests is to be takenfrom each batch. Hardness tests may additionally be required for certain types of forgings. (SeeW7.7.7.6).

W7.6.11 A batch testing procedure may also be used for hot rolled bars, not exceeding 250mm diameter,which are intended for the manufacture (by machining operations only) of straight shafting, bolts, studsand other components of similar shape. A batch is to consist of either:(i) material from the same piece or rolled length provided that where this is cut into individual

lengths, these are all heat treated in the same furnace charge, or(ii) bars of the same diameter and cast, heat treated in the same furnace charge and with a total mass

not exceeding 2,5 tonnes.

W7.6.12 Tensile and impact test specimens are to be machined to the dimensions given in W2.

W7.6.13 All tensile and impact tests are to be carried out at ambient temperature (generally 18-25°C)using test procedures in accordance with W3. Unless otherwise agreed all tests are to be carried out in thepresence of the Surveyors.

W7.6

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W7.7

W7.7 Mechanical properties(1980)

W7.7.1 Tables 2 and 3 give the minimum requirements for yield stress, elongation, reduction of areaand impact test energy values corresponding to different strength levels but it is not intended that theseshould necessarily be regarded as specific grades. The strength levels have been given in multiples of40N/mm2, or 50 N/mm2 in case of alloy steels, to facilitate interpolation for intermediate values ofspecified minimum tensile strength.The requirements given in these Tables relate to test specimens taken from subsurface positions, i.e. withtheir axis at a distance from the surface of up to 10% of the diameter or thickness. Where test specimensare taken at a greater distance from the surface (see W7.6.4) the values given in the Tables may bemodified at the discretion of individual Classification Societies.

W7.7.2 Forgings may be supplied to any specified minimum tensile strength selected within the generallimits detailed in Tables 2 or 3 but subject to any additional requirements of the relevant constructionRules.

W7.7.3 The results of all tensile tests are to comply with the requirements of Tables 2 or 3 appropriateto the type of steel, specified minimum tensile strength and the direction of test.

Table 2. Mechanical properties: carbon and carbon-manganese steel forgings

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Specified Yield Elongation Reduction Charpy test averageminimum stress on 5,65 √S0 of area energy (J) min.(3) Hardnesstensile (N/mm2) (%) min. (%) min. (Brinell)(4)

strength min. V-notch U-notch(N/mm2)(1), (2)

L T L T L T L T

360 180 28 20 50 35 32 18 30 20 95-135400 200 26 19 50 35 32 18 30 20 110-150440 220 24 18 50 35 32 18 30 20 125-160480 240 22 16 45 30 32 18 30 20 135-175

520 260 21 15 45 30 25 15 25 17 150-185560 280 20 14 40 27 25 15 25 17 160-200600 300 18 13 40 27 18 12 20 15 175-215640 320 17 12 40 27 18 12 20 15 185-230

680 340 16 12 35 24 18 12 20 15 200-240720 360 15 11 35 24 18 12 20 15 210-250760 380 14 10 35 24 18 12 20 15 225-265

L denotes longitudinal test specimen; T denotes transverse test specimen.

NOTES

1. For intermediate values of specified minimum tensile strength, the minimum values for yield stress, elongation, reduction of area and impact energy may be obtained by interpolation.

2. The following ranges for tensile strength may be additionally specified:specified minimum tensile strength < 600 N/mm2 ≥ 600 N/mm2

tensile strength range 120 N/mm2 150 N/mm2

3. When impact tests are required they are to be carried out at ambient temperature (18-25°C) and unless otherwise specified either Charpy V-notch or Charpy U-notch test specimens may be used at the option of the manufacturer.

4. The hardness values are typical and are given for information purposes only.

W7.7

Table 3. mechanical properties: Alloy steel forgings (quenched and tempered)

The average energy value from a set of three impact test specimens is to be not less than the appropriatevalue given in Tables 2 or 3. One individual value may be less than the required average value providedthat it is not less than 70% of this average value.

W7.7.4 The requirements of Table 3 are applicable to the general range of alloy steels used in marinepractice and at the discretion of individual Classification Societies may be modified for special types ofalloy steels.

W7.7.5 Where more than one tensile test is taken from a forging the variation in tensile strength is notto exceed the following:

Specified minimum tensile Difference in tensilestrength (N/mm2) strength (N/mm2)

<600 70≥600 <900 100

≥900 120

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Specified Yield Elongation Reduction Charpy test averageminimum stress on 5,65 √S0 of area energy (J) min.(4) Hardnesstensile (N/mm2) (%) min. (%) min. (Brinell)(5)

strength min.(3) V-notch U-notch(N/mm2)(1), (2)

L T L T L T L T

600 420 18 14 50 35 41 24 35 24 175-215650 450 17 13 50 35 32 22 30 23 190-235700 480 16 12 45 30 32 22 30 23 205-245750 530 15 11 45 30 32 20 30 22 215-260

800 590 14 10 40 27 32 20 30 22 235-275850 640 13 9 40 27 27 18 26 20 245-290900 690 13 9 40 27 27 18 26 20 260-320950 750 12 8 35 24 25 16 25 18 275-340

1000 810 12 8 35 24 25 16 25 18 290-3651050 870 11 7 35 24 21 13 23 15 310-3751100 930 11 7 35 24 21 13 23 15 320-385

L denotes longitudinal test specimen; T denotes transverse test specimen.

NOTES

1. For intermediate values of specified minimum tensile strength, the minimum values for yield stress, elongation, reduction of area and impact energy may be obtained by interpolation.

2. The following ranges for tensile strength may be additionally specified:specified minimum tensile strength < 900 N/mm2 ≥ 900 N/mm2

tensile strength range 150 N/mm2 200 N/mm2

3. The requirement for a minimum yield stress is not applicable to forgings which are intended for surface hardening by carburizing.

4. When impact tests are required they are to be carried out at ambient temperature (18-25°C) and unless otherwise specified either Charpy V-notch or Charpy U-notch test specimens may be used at the option of the manufacturer.

5. The hardness values are typical and are given for information purposes.

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W7.7.6 At the discretion of individual Classification Societies hardness tests may be required on thefollowing:(i) Gear forgings after completion of heat treatment and prior to machining the gear teeth. The

hardness is to be determined at four positions equally spaced around the circumference of the surface where teeth will subsequently be cut. Where the finished diameter of the toothed portion exceeds 2,5m, the above number of test positions is to be increased to eight. Where the width of a gear wheel rim forging exceeds 1,25m, the hardness is to be determined at eight positions at each end of the forging.

(ii) Small crankshaft and gear forgings which have been batch tested. In such cases at least one hardness test is to be carried out on each forging.

The results from these tests are to be to the satisfaction of the Surveyor and, for information purposes,typical Brinell hardness values are given in Tables 2 and 3.

W7.7.7 The variation in hardness on an individual forging or in a batch of small forgings is to complywith the following:

Specified minimum tensile Difference hardnessstrength (N/mm2) (Brinell number)

<600 not more than 25≥600 <900 not more than 35

≥900 not more than 42

Where other types of hardness tests are used, appropriate values may be obtained from conversion tables.

W7.7.8 Hardness tests may also be required on forgings which have been induction hardened, nitridedor carburized. For gear forgings these tests are to be carried out on the teeth after, where applicable, theyhave been ground to the finished profile. The results of such tests are to comply with the approvedspecifications (see W7.5.6).

W7.7.9 Where the result of a tensile test does not comply with the requirements, two additional testsmay be taken. If satisfactory results are obtained from both of these additional tests the forging or batchof forgings is acceptable. If one or both retests fail the forging or batch of forgings is to be rejected.

W7.7.10 Where the results from a set of three impact test specimens do not comply with therequirements (see W7.7.3) an additional set of three impact test specimens may be taken provided thatnot more than two individual values are less than the required average value and of these not more thanone is less than 70% of this average value. The results obtained are to be combined with the originalresults to form a new average which, for acceptance of the forgings or batch forgings, is to be not lessthan the required average value.

Additionally, for these combined results not more than two individual values are to be less than therequired average value and of these not more than one is to be less than 70% of this average value.

W7.7.11 The additional tests detailed in W7.7.9 and W7.7.10 are to be taken, preferably from materialadjacent to the original tests, but alternatively from another test position or sample representative of theforging or batch of forgings.

W7.7.12 At the option of the manufacturer, when a forging or a batch of forgings has failed to meet thetest requirements, it may be re-heat treated and re-submitted for acceptance tests.

W7.7

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W7.8 Inspection(1978)

W7.8.1 Before acceptance, all forgings are to be presented to the Surveyors for visual examination.Where applicable, this is to include the examination of internal surfaces and bores. Unless otherwiseagreed the verification of dimensions is the responsibility of the manufacturer.

W7.8.2 When required by the relevant construction Rules, or by the approved procedure for weldedcomposite components (see W7.2.9) appropriate nondestructive testing is also to be carried out beforeacceptance and the results are to be reported by the manufacturer.

All such tests are to be carried out by component operators using reliable and efficiently maintainedequipment. The testing procedures used are to be agreed with the Surveyors.

W7.8.3 Magnetic particle or liquid penetrant testing is to be carried out when the forgings are in thefinished condition. Where current flow methods are used for magnetization, particular care is to be takento avoid damaging finished machined surfaces by contact burns from the prods. Unless otherwise agreed,these tests are to be carried out in the presence of the Surveyor. Acceptance standards for defects foundby magnetic particle or liquid penetrant testing are to be to the satisfaction of the Classification Societyand in accordance with any specific requirements of the approved plan.

W7.8.4 Ultrasonic examination is to be carried out following the final heat treatment and at a stagewhen the forgings have been machined to a condition suitable for this type of examination. Both radialand axial scanning are to be carried out when appropriate for the shape and dimensions of the forgingbeing examined. Unless otherwise agreed this examination is to be carried out by the manufactureralthough Surveyors may request to be present in order to verify that the examination is being carried outin accordance with the agreed procedure.

W7.8.5 When required by the conditions of approval for surface hardened forgings (W7.5.6 refers)additional test samples are to be processed at the same time as the forgings which they represent. Thesetest samples are subsequently to be sectioned in order to determine the hardness, shape and depth of thelocally hardened zone and which are to comply with the requirements of the approved specification.

W7.8.6 In the event of any forging proving defective during subsequent machining or testing, it is to berejected notwithstanding any previous certification.

W7.9 Rectification of defective forgings(1978)

W7.9.1 Small surface imperfections may be removed by grinding or chipping and grinding. Completeelimination of these imperfections is to be proved by magnetic particle or liquid penetrant examination.At the discretion of the Surveyor, the resulting shallow grooves or depressions can be accepted, providedthat they are blended by grinding.

W7.9.2 Repairs by welding may only be considered in special circumstances and, in general, arerestricted to the rectification of defects of a minor nature in areas of low working stresses.

In such cases, full details of the proposed repair and subsequent inspection procedures are to besubmitted for the approval of the Surveyors prior to commencing the proposed specification. A statementand/or sketch detailing the extent and location of all repairs, together with details of the post weld heattreatment and nondestructive examination is to be provided for record purposes. The repair of compositecomponents formed by welding is to be carried out in accordance with the approved procedure (seeW.7.2.9).

W7.8 - W7.9

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W7.10 - W7.11

W7.10 Identification of forgings(1978)

W7.10.1 The manufacturer is to adopt a system of identification which will enable all finished forgingsto be traced to the original cast and the Surveyor is to be given full facilities for so tracing the forgingswhen required.

W7.10.2 Before acceptance, all forgings which have been tested and inspected with satisfactory resultsare to be clearly marked by the manufacturer. At the discretion of individual Classification Societies anyof the following particulars may be required:(i) Steel quality.(ii) Identification number, cast number or other marking which will enable the full history of the

forging to be traced.(ii) Manufacturer's name or trade mark.(iv) The Classification Society's name, initials or symbol.(v) Abbreviated name of the Classification Society's local office.(vi) Personal stamp of Surveyor responsible for inspection.

W7.10.3 Where small forgings are manufactured in large numbers, modified arrangements foridentification may be specially agreed with the Classification Society.

W7.11 Certification

W7.11.1 The manufacturer is to provide the Surveyor with a test certificate or shipping statement givingthe following particulars for each forging or batch of forgings which has been accepted.:(i) Purchaser's name and order number.(ii) Description of forgings and steel quality.(iii) Identification number.(iv) Steelmaking process, cast number and chemical analysis of ladle sample.(v) Results of mechanical tests.(vi) General details of heat treatment.

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W8

Hull and machinery steel castings

W8.1 Scope(1978)

W8.1.1 All important steel castings, as defined in the relevant construction Rules, are to bemanufactured and tested in accordance with the requirements of the following paragraphs.

W8.1.2 These requirements are applicable only to steel castings where the design and acceptance testsare related to mechanical properties at ambient temperature. For other applications, additionalrequirements may be necessary, especially when the castings are intended for service at low or elevatedtemperatures.

W8.1.3 Specific requirements are given for carbon and carbon-manganese steel castings but,alternatively, castings which comply with national or proprietary specifications may be acceptedprovided such specifications give reasonable equivalence to these requirements or are otherwisespecially approved or required by the Classification Society.

W8.1.4 Specific requirements are not given for alloy steel castings and where the use of such materialsis proposed full details of the chemical composition, heat treatment and mechanical properties are to besubmitted for approval of the Classification Society.

W8.1.5 Where small castings are produced in large quantities, the manufacturer may adopt alternativeprocedures for testing and inspection subject to the approval of the Classification Society.

W8.2 Manufacture(1978)

W8.2.1 All important castings are to be made at foundries where the manufacturer has demonstrated tothe satisfaction of the Classification Society that the necessary manufacturing and testing facilities areavailable and are supervised by qualified personnel. A programme of approval tests may be required inaccordance with the procedures of individual Classification Societies.

W8.2.2 Steel is to be manufactured by the open hearth, electric or basic oxygen process or by otherprocesses approved by the Classification Society.

W8.2.3 All flame cutting, scarfing or arc-air gouging to remove surplus metal is to be undertaken inaccordance with recognized good practice and is to be carried out before the final heat treatment.Preheating is to be employed when necessitated by the chemical composition and/or thickness of thecastings. If necessary, the affected areas are to be either machined or ground smooth.

W8.2.4 For certain components the proposed method of manufacture may require special approval bythe Classification Society.

W8.2.5 Where castings of the same type are produced in regular quantities, the manufacturer is to makeany tests necessary to prove the quality of the prototype castings and is also to make periodicalexaminations to verify the continued efficiency of the manufacturing technique. The Surveyor is to begiven the opportunity to witness these tests.

W8.2.6 When two or more castings are joined by welding to form a composite item, details of theproposed procedure are to be submitted for approval. Welding procedure tests may be required.

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W8.3 Quality of castings(1978)

W8.3.1 All castings are to be free from surface or internal defects which would be prejudicial to theirproper application in service. The surface finish is to be in accordance with good practice and anyspecific requirements of the approved plan.

W8.4 Chemical composition(1978)

W8.4.1 All castings are to be made from killed steel and the chemical composition is to be appropriatefor the type of steel and the mechanical properties specified for the castings.

W8.4.2 For carbon and carbon-manganese steel castings the chemical composition of ladle samples isto comply with the following the overall limits.

Carbon 0,40% max.Silicon 0,60% max.Manganese 0,50-1,60%Sulphur 0,040% max.Phosphorous 0,040% max.

Residual elements:Copper 0,30% max.Chromium 0,30% max.Nickel 0,40% max.Molybdenum 0,15% max.

W8.4.3 For alloy steel castings the chemical composition of ladle samples is to comply with theapproved specification (see W8.1.4).

W8.4.4 Unless otherwise required suitable grain refining elements such as aluminium may be used atthe discretion of the manufacturer. The content of such elements is to be reported in the ladle analysis.

W8.4.5 Where steel castings are intended for welded construction, the proposed chemical compositionis subject to approval by the Classification Society.

W8.5 Heat treatment (including straightening)(1978)

W8.5.1 Castings are to be supplied in one of the following conditions:Fully annealedNormalizedNormalized and temperedQuenched and tempered.

The tempering temperature is to be not less than 550°C.

W8.5.2 Castings for components such as crankshafts and engine bedplates, where dimensional stabilityand freedom from internal stresses are important, are to be given a stress relief heat treatment. This is tobe carried out at a temperature of not less than 550°C followed by furnace cooling to 300°C or lower.

W8.5.3 Heat treatment is to be carried out in properly constructed furnaces which are efficientlymaintained and have adequate means for control and recording of temperature. The furnace dimensionsare to be such as to allow the whole casting to be uniformly heated to the necessary temperature. In thecase of very large castings alternative methods for heat treatment will be specially considered by theClassification Society.

W8.5.4 If a casting is locally reheated or any straightening operation is performed after the final heattreatment, a subsequent stress relieving heat treatment may be required in order to avoid the possibility ofharmful residual stresses.

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W8.6 Mechanical tests(1978)

W8.5.1 Test material, sufficient for the required tests and for possible re-test purposes is to be providedfor each casting or batch of castings.

W8.6.2 At least one test sample is to be provided for each casting. Unless otherwise agreed these testsamples are to be either integrally cast or gated to the castings and are to have a thickness of not less than30mm.

W8.6.3 Where the casting is of complex design or where the finished mass exceeds 10 tonnes, two testsamples are to be provided. Where large castings are made from two or more casts, which are not mixedin a ladle prior to pouring, two or more test samples are to be provided corresponding to the number ofcasts involved. These are to be integrally cast at locations as widely separated as possible.

W8.6.4 For castings where the method of manufacture has been specially approved by theClassification Society in accordance with W8.2.4, the number and position of test samples is to be agreedwith the Classification Society having regard to the method of manufacture employed.

W8.6.5 As an alternative to W8.6.2, where a number of small castings of about the same size is madefrom one cast and heat treated in the same furnace charge, a batch testing procedure may be adoptedusing separately cast test samples of suitable dimensions. At least one test sample is to be provided foreach batch of castings.

W8.6.6 All test samples are to be suitably marked to identify them with the castings which theyrepresent.

W8.6.7 The test samples are to be heat treated together with the castings which they represent.

W8.6.8 One tensile test specimen and, when required, one set of three impact test specimens are to betaken from each test sample. When impact tests are required either Charpy V-notch or Charpy U-notchimpact test specimens may be used at the discretion of the manufacturer unless otherwise specified by theClassification Society.

W8.6.9 Tensile and impact test specimens are to be machined to the dimensions given in W2.

W8.6.10 All tensile and impact tests are to be carried out at ambient temperature (generally 18°-25°C)using test procedures in accordance with W2. Unless otherwise agreed all tests are to be carried out in thepresence of the Surveyors.

W8.7 Mechanical properties(1978)

W8.7.1 Table 1 gives the minimum requirements for yield stress, elongation, reduction of area andimpact test energy values corresponding to different strength levels for carbon and carbon-manganesesteel castings. It is not intended that these should necessarily be regarded as specific grades. The strengthlevels have been given in multiples of 40 N/mm2 to facilitate interpolation for intermediate values ofspecified minimum tensile strength.

W8.7.2 Castings may be supplied to any specified minimum tensile strength selected within the generallimits detailed in Table 1 but subject to any additional requirements of the relevant construction Rules.

W8.7.3 The results of all tensile tests are to comply with the requirements of Table 1, appropriate to thequality of steel and the specified minimum tensile strength. The average energy value from a set of threeimpact test specimens is to be not less than the appropriate value given in Table 1. One individual valuemay be less than the required average value provided that it is not less than 70% of this average value.

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W8.8 Inspection(1978)

W8.8.1 All castings are to be cleaned and adequately prepared for examination; suitable methodsinclude pickling, caustic cleaning, wire brushing, local grinding, shot or sand blasting. The surfaces arenot to be hammered, peened or treated in any way which may obscure defects.

W8.8.2 Before acceptance all castings are to be presented to the Surveyors for visual examination.Where applicable, this is to include the examination of internal surfaces. Unless otherwise agreed, theverification of dimensions is the responsibility of the manufacturer.

W8.8.3 When required by the relevant construction Rules, or by the approved procedure for weldedcomposite components (see W8.2.6.), appropriate nondestructive testing is also to be carried out beforeacceptance and the results are to be reported by the manufacturer. All such tests are to be carried out bycompetent operators, using reliable and efficiently maintained equipment. The testing procedures usedare to be agreed with the Surveyors.

W8.8.4 Magnetic particle or liquid penetrant testing is to be carried out when the castings are in thefinished condition. Where current flow methods are used for magnetization, particular care is to be takento avoid damaging finished machined surfaces by contact burns from the prods. Unless otherwise agreedthese tests are to be carried out in the presence of the Surveyors. Acceptance standards are to be to thesatisfaction of the Society and in accordance with any requirements of the approved plan.

W8.8.5 The radiographic examination of castings is to be carried out by the manufacturer at positionsindicated on the approved plan or as otherwise agreed with the Surveyors. All radiographics are to besubmitted to the Surveyors for examination and acceptance. Acceptance standards are to be to thesatisfaction of the Classification Society and in accordance with any requirements of the approved plan.

W8.8.6 The ultrasonic examination of castings is to be carried out at positions as indicated on theapproved plan or as otherwise agreed with the Surveyors. This examination is to be carried out by themanufacturer but Surveyors may request to be present in order to verify that the examination is beingcarried out in accordance with the agreed procedure.

W8.8.7 When required by the relevant construction Rules castings are to be pressure tested before finalacceptance. These tests are to be carried out in the presence of the Surveyors and are to be to theirsatisfaction.

W8.8.8 In the event of any casting proving defection during subsequent machining or testing it is to berejected notwithstanding any previous certification.

W8.9 Rectification of defective castings(1978)

W8.9.1 When unacceptable defects are found in a casting these are to be removed by machining orchipping. Flame-scarfing or arc-air gouging may also be used provided that pre-heating is employedwhen necessary and that the surfaces of the resulting depression are subsequently ground smooth.Complete elimination of the defective material is to be proved by adequate nondestructive testing.Shallow grooves or depression resulting from the removal of defects may, at the discretion of theSurveyor, be accepted provided that they will cause no appreciable reduction in the strength of thecastings and that they are suitably smoothed and contoured by grinding.

W8.9.2 Proposals to repair a defective casting by welding are to be submitted to the Surveyors forapproval before this work is commenced. Such proposals are to include details of the extent and positionof all defects. The manufacturer may be required to carry out welding procedure tests to demonstrate thatsatisfactory mechanical properties can be obtained.

W8.8 - W8.9

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W8.9.3 When it has been agreed that the casting can be repaired this is to be carried out in accordancewith an approved welding procedure which includes the following features:(i) Cast steel components for crankshafts and alloy steel castings are to be given a suitable

preliminary heat treatment prior to carrying out weld repairs. A similar heat treatment may also be required for other types of castings where the repair of a major defect is proposed.

(ii) The excavations are to be suitably shaped to allow good access for welding and after final preparation for welding are to be re-examined by suitable nondestructive testing methods to ensure that all defective material has been eliminated.

(iii) All castings in alloy steels and all castings for crankshafts are to be suitably pre-heated prior to welding. Castings in carbon or carbon-manganese steel may also require to be pre-heated depending on their chemical composition and the dimensions and position of the weld repairs.

(iv) Welding is to be done under cover in positions free from draughts and adverse weather conditions by qualified welders with adequate supervision. As far as possible, all welding is to be carried out in the downhand (flat) position.

(v) The welding consumables used are to be of a type giving a weld deposit with mechanical properties similar to those of the parent castings. The use of low hydrogen type welding consumables is preferred.Consideration is to be given to the effect of postweld heat treatment on the mechanical properties of the weld material.

(vi) After welding has been completed the castings are to be given either a suitable heat treatment in accordance with the requirements of W8.5.1 or a stress relieving heat treatment at a temperature of not less than 550°C. The type of heat treatment employed will be dependent on the chemical composition of the casting and the dimensions, positions and nature of the defects.

(vii) Special consideration may be given to the omission of postweld heat treatment or to the acceptance of local stress-relieving heat treatment where the repaired area is small and machining of the casting has reached an advanced stage.

(viii) On completion of heat treatment the weld repairs and adjacent material are to be ground smooth and examined by magnetic particle or liquid penetrant testing. Supplementary examination by ultrasonics or radiography may also be required depending on the dimensions and nature of the original defect. Satisfactory results are to be obtained from all forms of nondestructive testing used.

W8.10 Identification of castings(1978)

W8.10.1 The manufacturer is to adopt a system of identification which will enable all finished castingsto be traced to the original cast and the Surveyors are to be given full facilities for so tracing the castingswhen required.

W8.10.2 Before acceptance, all castings which have been tested and inspected with satisfactory resultsare to be clearly marked by the manufacturer. At the discretion of individual Classification Societies anyof the following particulars may be required:(i) Steel quality.(ii) Identification number, cast number or other marking which will enable the full history of the

casting to be traced.(iii) Manufacturer's name or trade mark.(iv) The Classification Society's name, initials or symbol.(v) Abbreviated name of the Classification Society's local office.(vi) Personal stamp of Surveyors responsible for inspection.(vii) Where applicable, test pressure.

W8.10.3 Where small castings are manufactured in large numbers, modified arrangements foridentification may be specially agreed with the Classification Society.

W8.9 - W8.10

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W8.11 Certification(1978)

W8.11.1 The manufacturer is to provide the Surveyor with a test certificate or shipping statement givingthe following particulars for each casting or batch of castings which has been accepted:(i) Purchaser's name and order number.(ii) Description of castings and steel quality.(iii) Identification number.(iv) Steel making process, cast number and chemical analysis of ladle samples.(v) Results of mechanical tests.(vi) General details of heat treatment.(vii) Where applicable, test pressure.

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W8.11

IACS Req. 1980/Rev. 1 1995

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Normal and higher strength hull structural steels1. Scope

1.1 These requirements apply to weldable normal and higher strength hot-rolled steel plates, wide flats, sections and bars intended for use in hull construction.

1.2 The requirements are primarily intended to apply to steel products with a thickness as follows:For steel plates and wide flats;

- Grades A, B, D, E, A32, D32, E32, A36, D36 and E36: Up to 100mm in thickness

- Grades A40, D40, E40, F32, F36 and F40 : Up to 50mm in thickness

For sections and bars;

- All Grades : Up to 50mm in thickness

For greater thickness certain variations in the requirements may be allowed or required in particular cases after consideration of the technical circumstances involved.

1.3 Provision is made for four grades of normal strength steel based on the impact test requirements. For higher strength steels provision is made for three strength levels (315, 355 and 390 N/mm2)each subdivided into four grades based on the impact test temperature.

1.4 Steels differing in chemical composition, deoxidation practice, conditions of supply and mechanical properties may be accepted, subject to the special approval of the Classification Society. Such steels are to be given a special designation.

NOTE:.

1. The attention of the users must be drawn to the fact that when fatigue loading is present, the effective fatigue strength of a welded joint of higher strength steel may not be greater than that of a welded joint in normal strength steels.

2. Before subjecting steels produced by thermo-mechanical rolling to further heating for forming or stress relieving, or using high heat-input welding, special consideration must be given to the possibility of a consequent reduction in mechanical properties.

W11(1979)(Rev.11986)(Rev. 21995 v.2.1)

W11.1

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11-1

IACS Req. 1979/Rev. 2 1995,v2.1

2. Approval

2.1 All materials are to be manufactured at works which have been approved by the Classification Society for the type and grade of steel which is being supplied.

2.2 The stability of each grade of steel for forming and welding is to be demonstrated during the initial approval tests at the steelworks. The type and extent of testing required is at the discretion of the Classification Societies.

2.3 When steel is not produced at the works at which it is rolled, a certificate is to be supplied to the Surveyor at the rolling mill stating the process by which it was manufactured, the name of the manufacturer who supplied it, the number of the cast from which it was made and the ladle analysis. The Surveyor is to have access to the works at which the steel was produced.

3. Method of Manufacture

3.1 Steel is to be manufactured by the basic oxygen, electric furnace or open hearth processes or by other processes specially approved by the Classification Society.

3.2 The deoxidation practice used for each grade is to comply with the appropriate requirements of Tables 1 and 2.

3.3 The applicable rolling procedures are defined as follows and the schematic diagrams are given in the Appendix.

(i) Controlled Rolling, CR (Normalizing Rolling, N):A rolling procedure in which the final deformation is carried out in the normalising temperature range, resulting in a material condition generally equivalent to that obtained by normalising.

(ii) Thermo-mechanical Rolling, TM (Thermo-mechanical Controlled Processing, TMCP):This is a procedure which involves the strict control of both the steel temperature and the rolling reduction. Generally a high proportion of the rolling reduction is carried out close to the Ar3 temperature and may involve the rolling in the dual phase temperature region. Unlike controlled rolled (normalised rolling) the properties conferred by TM (TMCP) cannot be reproduced by subsequent normalising or other heat treatment.

The use of accelerated cooling on completion of TM-rolling may also be accepted subject to the special approval of the Society. The same applies for the use of tempering after completion of theTM-rolling.

(iii) Accelerated Cooling, AcCAccelerated cooling is a process, which aims to improve mechanical properties by controlled cooling with rates higher than air cooling immediately after the final TM-rolling operation. Directquenching is excluded from accelerated cooling.

The material properties conferred by TM and AcC cannot be reproduced by subsequent normalising or other heat treatment.

W11.2–W11.3

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11-2

4. Chemical Composition

4.1 The chemical composition of samples taken from each ladle of each cast is to be determined by the manufacturer in an adequately equipped and competently staffed laboratory and is to comply with the appropriate requirements of Tables 1 and 2. For steel plates and wide flats over 50mm thick, slight deviations in the chemical composition may be allowed as approved by the Classification Society.

4.2 The manufacturer's declared analysis will be accepted subject to occasional checks if required by the Surveyor.

Table 1 Chemical composition and deoxidation practice for normal strength steels

t = thickness

Notes:

1. Grade A sections up to a thickness of 12.5 mm may be accepted in rimmed steel subject to the special approval of the Classification Society.

2. Max. 0.23% for sections.3. When Grade B steel is impact tested the minimum manganese content may be reduced to 0.60%.4. When any grade of steel is supplied in the thermo-mechanically rolled condition variations in the

specified chemical composition may be allowed or required by the Classification Society.5. For Grade D steel over 25 mm thick.6. For Grade D steel over 25 mm thick and Grade E steel the total aluminium content may be

determined instead of acid soluble content. In such cases the total aluminium content is to be not less than 0.020%. A maximum aluminium content may also be specified by the Classification Society. Other suitable grain refining elements may be used subject to the special approval of the Classification Society.

7. The Classification Society may limit the amount of residual elements which may have an adverse effect on the working and use of the steel, e.g. copper and tin.

8. Where additions of any other element have been made as part of the steelmaking practice, the content is to be indicated.

W11.4

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11-3

Grade A B D E

Deoxidation For t ≤ 50 mm For t ≤ 50 mm For t ≤ 25mm KilledPractice Any method Any method killed and fine

except rimmed steel (1) except rimmed For t > 25 mm grain treatedFor t > 50 mm For t > 50 mm Killed and

Killed Killed fine grain treated

Chemical Carbon plus of the manganese content is not to exceed 0,40%Composition % (4) (7) (8)(ladle samples)C max. 0,21 (2) 0,21 0,21 0,18Mn min. 2,5 x C 0,80 (3) 0,60 0,70Si max. 0,50 0,35 0,35 0,35P max. 0,035 0,035 0,035 0,035S max. 0,035 0,035 0,035 0,035Al (acid soluble) min. – – 0,015 (5) (6) 0,015 (6)

16

Table 2 Chemical composition and deoxidation practice for higher strength steels

Notes:

1. The letter “H” may be added either in front or behind the grade mark e.g. HA 32 or AH 32.2. Up to a thickness of 12.5 mm the minimum manganese content may be reduced to 0.70%.3. The total aluminium content may be determined instead of the acid soluble content.

In such cases the total aluminim content is to be not less than 0.020%.4. The steel is to contain aluminium, niobium, vanadium or other suitable grain refining elements,

either singly or in any combination. When used singly the steel is to contain the specified minimum content of the grain refining element. When used in combination, the specified minimum content of a fine graining element is not applicable.

5. When any grade of higher strength steel is supplied in the thermo-mechanically rolled condition variations in the specified chemical composition may be allowed or required by the Classification Society.

6. When required, the carbon equivalent value is to be calculated from the ladle analysis using the following formula.

This formula is applicable only to steels which are basically of the carbon-manganese type and gives a general indication of the weldability of the steel.

7. Where additions of any other element have been made as part of the steelmaking practice, the content is to be indicated.

IACS Req. 1979/Rev. 2 1995, v2.1

W11.4

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Ceq CMn Cr Mo V Ni Cu

= + + ++ + +

6 5 15(%)

11-4

Grade (1) A32 D32 E32 F32A36 D36 E36 F36A40 D40 E40 F40

Deoxidation Practice killed and fine grain treated

Chemical Composition % (5) (7)(ladle samples)C max. 0.18 0.16Mn 0.90 - 1.60 (2) 0.90-1.60Si max. 0.50 0.50P max. 0.035 0.025S max. 0.035 0.025Al (acid soluble) min. 0.015 (3) (4) 0.015 (3) (4)Nb 0.02 - 0.05 (4) ) total: 0.02-0.05(4) ) total:V 0.05 - 0.10 (4) ) 0.12 0.05-0.10(4) ) 0.12Ti max. 0.02 ) max. 0.02 ) max.Cu max. 0.35 0.35Cr max. 0.20 0.20Ni max. 0.40 0.80Mo max. 0.08 0.08N max. - 0.009 (0.012 if A1 is present)Carbon Equivalent (6)

IACS Req. 1979/Rev. 2 1995, V2.1

W11.4

4.3 For TM (TMCP) steels the following special requirements apply:

(i) The carbon equivalent value is to be calculated from the ladle analysis using the following formula and to comply with the requirements of Table 3;

(ii) The following formula (cold cracking susceptibility) may be used for evaluating weldability instead of the carbon equivalent at the discretion of the Classification Society;

In such cases the cold cracking susceptibility value required may be specified by theClassification Society.

Table 3 Carbon equivalent for higher strength steels up to 100mm inthickness produced by TM.

t: thickness (mm)

NOTES:

(1) It is a matter for the manufacturer and shipbuilder to mutually agree in individual cases as to whether they wish to specify a more stringent carbon equivalent.

(2) Grades F32 and F36 steels over 50 mm in thickness are not applicable.

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Ceq CMn Cr Mo V Ni Cu

= + + ++ + +

6 5 15(%)

Pcm CSi Mn Cu Ni Cr Mo V

= + + + + + + + +30 20 20 60 20 15 10

5

11-5

Grade Carbon Equivalent, max. (%) (1)

t < 50 50 < t < 100

A32, D32, E32, F32 0.36 0.38 (2)

A36, D36, E36, F36 0.38 0.40 (2)

A40, D40, E40, F40 0.40 -

W11.5

5. Condition of Supply

5.1 All materials are to be supplied in a condition complying with the appropriate requirements of Tables 4 and 5.

Table 4 Condition of supply for normal strength steels (1)

NOTES:

(1) These conditions of supply and the impact test requirements are summarised in Table 8.(2) Subject to the special approval of the Classification Society, Grades A and B steel plates may be

supplied in the as rolled condition - see 11.13.2 (ii).(3) Subject to the special approval of the Classification Society, sections in Grade D steel may be

supplied in the as rolled condition provided satisfactory results are consistently obtained from Charpy V-notch impact tests. Similarly sections in Grade E steel may be supplied in the as rolled or controlled rolled condition. The frequency of impact tests is to be in accordance with W11.13.2 (ii) and W11.13.3 (iii) respectively.

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11-6

Grades Thickness Condition of Supply

A < 50 mm Any> 50 mm < 100 mm Normalized, controlled rolled or thermo-mechanically

rolled (2)B < 50 mm Any

> 50 mm < 100 mm Normalized, controlled rolled or thermo-mechanicallyrolled (2)

D < 35 mm Any> 35 mm < 100 mm Normalized, controlled rolled or thermo-mechanically

rolled (3)E < 100 mm Normalized or thermo-mechanically rolled (3)


W11.5–W11.6

Table 5 Condition of supply for higher strength steels (1)

NOTES:(1) These conditions of supply and the requirements for impact tests are summarised in Table 9.(2) The frequency of impact tests is to be in accordance with W11.13.2 (ii).(3) Subject to the special approval of the Classification Society, sections in Grades A32, A36, D32

and D36 steels may be supplied in the as rolled condition provided satisfactory results are consistentlyobtained from Charpy V-notch impact tests. Similarly sections in Grades E32 and E36 steels maybe supplied in the as rolled or controlled rolled condition. The frequency of impacttests is to be in accordance with W11.13.2 (ii) and W11.13.2 (iii) respectively.

(4) Subject to the special approval of the Classification Society, sections in Grades F32 and F36 steelsmay be supplied in the controlled rolled condition. The frequency of impact tests is to be in accordance with W11.13.3 (iii).

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11-7

Grades Grain Refining Thickness Condition of supplyElements Used

A32 Nb and/or V ≤ 12.5mm AnyA36 > 12,5mm ≤ 100mm Normalized, controlled rolled or

thermo-mechanically rolled (3)

A32 Al alone ≤ 20mm AnyA36 or with Ti > 20mm ≤ 35mm Any, as rolled subject to special approval of

the Classification Society (2)> 35mm ≤ 100mm Normalized, controlled rolled or


A40 Any ≤ 12.5 mm Any>12.5 mm ≤ 50mm Normalized, controlled rolled or thermo-

mechanically rolled

D32 Nb and/or V ≤ 12.5mm AnyD36 > 12.5mm ≤ 100mm Normalized, controlled rolled or


D32 Al alone ≤ 20mm AnyD36 or with Ti > 20 mm ≤ 25mm Any, as rolled subject to special approval of

the Classification Society (2)>25 mm ≤ 100 mm Normalized, controlled rolled or thermo-

mechanically rolled (3)

D40 Any ≤ 50 mm Normalized, controlled rolled or thermo-mechanically rolled

E32 Any ≤ 50 mm Normalized or thermo-mechanically E36 rolled (3)

> 50 mm ≤ 100 mm Normalized, thermo-mechanically rolledE40 Any ≤ 50 mm Normalized, thermo-mechanically rolled or

quenched and temperedF32 Any ≤ 50 mm Normalized, thermo-mechanically rolledF36 or quenched and tempered (4)F40

IACS Req. 1979/Rev. 2 1995, v2.1

W11.6

6. Mechanical Properties

6.1 For tensile test either the upper yield stress (ReH) or where ReH cannot be determined, the 0.2percent proof stress (Rp 0.2) is to be determined and the material is considered to comply with therequirements if either value meets or exceeds the specified minimum value for yield strength (Re).

6.2 The results obtained from tensile tests are to comply with the appropriate requirements of Tables 6 and 7.

Table 6 Mechanical properties for normal strength steels

NOTES:(1) For all thicknesses of Grade A sections the upper limit for the specified tensile strength range may

be exceeded at the discretion of the Classification Society. (2) For full thickness flat tensile test specimens with a width of 25 mm and a gauge length of 200mm

the elongation is to comply with the following minimum values :

(3) See paragraph W11.6.3.(4) Charpy V-notch impact tests are generally not required for Grade B steel with thickness of 25 mm

or less.(5) Impact tests for Grade A over 50 mm thick are not required when the material is produced using

fine grain practice and furnished normalised. TM rolling may be accepted without impact testing at the discretion of the Society.

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Thickness mm > 5 > 10 > 15 > 20 > 25 > 30 > 40≤ 5 ≤ 10 ≤ 15 ≤20 ≤ 25 ≤ 30 ≤ 40 ≤ 50

Elongation % 14 16 17 18 19 20 21 22

▲

11-8

Impact Test

Grade Yield Tensile Elongation Test Average Impact Energy (J)Strength Strength (5.65 √S0) Temp. min

ReH (N/mm2) Rm (N/mm2) A5 (%) °C t ≤ 50 (mm) 50<t ≤ 70(mm) 70 <t ≤ 100(mm)

min Long (3) Trans (3) Long (3) Trans (3) Long (3) Trans (3)

A +20 – – 34(5) 24(5) 41(5) 27(5)B 235 400/520 (1) 22 (2) 0 27 (4) 20 (4) 34 24 41 27 D -20 27 20 34 24 41 27 E -40 27 20 34 24 41 27

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W11.6

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Table 7 Mechanical properties for higher strength steels

t: thickness (mm)

NOTES:(1) For full thickness flat tensile test specimens with a width of 25mm and a gauge length of

200 mm the elongation is to comply with the following minimum values:

(2) See paragraph W11.6.3.(3) For Grades A32 and A36 steels a relaxation in the number of impact tests for acceptance purposes

may be permitted by special agreement with the Classification Society provided that satisfactory results are obtained from occasional check tests.

6.3 Minimum average energy values are specified for Charpy V-notch impact test specimens taken in either the longitudinal or transverse directions (see W11.12.2). Generally only longitudinal test specimens need to be prepared and tested except for special applications where transverse test specimens may be required by the purchaser or the Classification Society. Transverse test results areto be guaranteed by the supplier.

11-9

Grade Yield Tensile Elongation Impact TestStrength Strength (5.65 √S0) Average Impact Energy (J)

ReH (N/mm2) Rm (N/mm2) A5(%) Test min

Temp. t ≤ 50(mm) 50 <t ≤ 70(mm) 70 <t ≤ 100(mm)min ( °C) Long (2) Trans (2) Long (2) Trans (2) Long (2) Trans (2)

A32 0 31 (3) 22 (3) 38 26 46 31D32 315 440/570 22 (1) –20 31 22 38 26 46 31 E32 –40 31 22 38 26 46 31F32 -60 31 22 Not applicable

A36 0 34 (3) 24 (3) 41 27 50 34D36 355 490/630 21 (1) –20 34 24 41 27 50 34E36 –40 34 24 41 27 50 34F36 -60 34 24

A40 0 41 27D40 390 510/660 20(1) -20 41 27 Not applicableE40 -40 41 27F40 -60 41 27

Thickness Grade > 5 > 10 > 15 > 20 > 25 > 30 > 40(mm) ≤ 5 ≤ 10 ≤ 15 ≤20 ≤ 25 ≤ 30 ≤ 40 ≤ 50

Elongation A32, D32, E32 & F32 14 16 17 18 19 20 21 22% A36, D36, E36 & F36 13 15 16 17 18 19 20 21

A40, D40, E40 & F40 12 14 15 16 17 18 19 20

IACS Req. 1979/Rev. 2 1995, v2.1

W11.6-W11.10

The tabulated values are for standard specimens 10 mm x 10 mm. For plate thicknesses less than 10 mm,impact test may be waived at the discretion of the Classification Society or sub-size specimens may beused with reduced requirements as follows :

Specimen 10 mm x 7.5 mm : 5/6 of tabulated energySpecimen 10 mm x 5 mm : 2/3 of tabulated energy

6.4 The average value obtained from one set of three impact tests is to comply with the requirementsgiven in Tables 6 and 7. One individual value only may be below the specified average value provided itis not less than 70% of that value.

6.5 Generally, impact tests are not required when the nominal plate thickness is less than 6 mm.

7. Freedom from Defects

7.1 The steel is to be reasonably free from segregations and non-metallic inclusions. The finished material is to have a workmanlike finish and is to be free from internal and surface defects prejudicial to the use of the material for the intended application.

7.2 The acceptance criteria for surface finish and procedures for the repair of defects, as detailed in Recommendation, No 12, "Guidance for the Surface Finish of Hot Rolled Steel Plates and Wide Flats" are to be observed.

8. Tolerances

8.1 Unless otherwise agreed or specially required the thickness tolerances in Unified Requirement W13 "Allowable under thickness tolerances of steel plates and wide flats" are applicable.

9. Identification of Materials

9.1 The steelmaker is to adopt a system for the identification of ingots, slabs and finished pieces which will enable the material to be traced to its original cast.

9.2 The Surveyor is to be given full facilities for so tracing the material when required.

10. Testing and Inspection

10.1 Facilities for InspectionThe manufacturer is to afford the Surveyor all necessary facilities and access to all relevant parts of the works to enable him to verify that the approved process is adhered to, for the selection of test materials, and the witnessing of tests, as required by the Rules, and for verifying the accuracy of the testing equipment.

10.2 Testing ProceduresThe prescribed tests and inspections are to be carried out at the place of manufacture before dispatch. The test specimens and procedures are to be in accordance with Unified Requirement W2 “Test Specimens and Mechanical Testing Procedures for Materials”. All the test specimens are to be selected and stamped by the Surveyor and tested in his presence, unless otherwise agreed.

10.3 Through Thickness Tensile Tests

If plates and wide flats with thickness of 15 mm and over are ordered with through thickness properties, the through thickness tensile test in accordance with Unified Requirement W14 “Steel Plates and Wide Flats with Improved Through Thickness Properties” is to be carried out.

W11cont’d

▲

11-10

10.4 Ultrasonic Inspection

If plates and wide flats are ordered with ultrasonic inspection, this is to be made in accordance with an accepted standard at the discretion of the Classification Society.

10.5 Surface Inspection and Dimensions

Surface inspection and verification of dimensions are the responsibility of the steel maker. The acceptance by the Classification Society’s Surveyor shall not absolve the steel maker from this responsibility.

11. Test Material

11.1 Definitions(a) Piece: the term "piece" is understood to mean the rolled product from a single slab, billet or

ingot if this is rolled directly into plates, sections or bars.(b) Batch: a number of similar pieces presented as a group for acceptance tests.

11.2 Test Samples(a) All material in a batch presented for acceptance tests is to be of the same product form e.g.

plates, flats, sections, etc. from the same cast and in the same condition of supply.(b) The test samples are to be fully representative of the material and, where appropriate, are not

to be cut from the material until heat treatment has been completed.(c) The test specimens are not to be separately heat treated in any way.

(d) Unless otherwise agreed the test samples are to be taken from the following positions:

(i) Plates and flats with a width ≥ 600 mm. The test samples are to be taken from one end at a position approximately midway between the axis in the direction of the rolling and the edge of the rolled product (see Fig. 1). Unless otherwise agreed the tensile test specimens are to be prepared with their longitudinal axes transverse to the final direction of rolling.

(ii) Flats with a width < 600 mm, bulb flats and other sections. The test samples are to be taken from one end at a position approximately one third from the outer edge (see Figs. 2, 3 and 4) or in the case of small sections, as near as possible to this position. In the case of channels, beams or bulb angles, the test samples may alternatively be taken from a position approximately one quarter of the width from the web centre line or axis (see Fig. 3). The tensile test specimens may be prepared with their longitudinal axes either parallel or transverse to the final direction of rolling.

(iii) Bars and other similar products. The test samples are to be taken so that the longitudinal axes of the test specimens are parallel to the direction of rolling and are as near as possible to the following– for non-cylindrical sections, at one third of the half diagonal from the outside,– for cylindrical sections, at one third of the radius from the outside (see Fig. 6).

IACS Req. 1979/Rev. 2 1995, v2.1

W11.10.5-W11.11.2

W11cont’d

▲

▲

11-11

Fig. 1 Plates and flats

��1/2

1/4

1/4

Fig. 2 Angles

�2/3 1/3

�2/31/3

1/2

1/4

1/4

Fig. 3 Channel


W11.12-W11.13.2

12. Mechanical Test specimens

12.1 Tensile Test Specimens. The dimensions of the tensile test specimens are to be in accordance with Unified Requirement, W2. Generally for plates, wide flats and sections flat test specimens of full product thickness are to be used. Round test specimens may be used when the product thickness exceeds 40 mm or for bars and other similar products. Alternatively for small sizes of bars, etc. test specimens may consist of a suitable length of the full cross section of the product.

12.2 Impact Test Specimens. The impact test specimens are to be of the Charpy V-notch type cut with their edge within 2 mm from the “as rolled” surface with their longitudinal axes either parallel(indicated “Long” in Table 6 & 7) or transverse (indicated "Trans" in Tables 6 & 7) to the finaldirection of rolling of the material. The notch is to be cut in a face of the test specimen which wasoriginally perpendicular to the rolled surface. The position of the notch is not to be nearer than 25mm to a flame cut or sheared edge (see also W11.6.3). Where the product thickness exceeds 40mm, the impact test specimens are to be taken with their longitudinal axis at a quarter thicknessposition.

13. Number of Test Specimens

13.1 Number of Tensile Tests. For each batch presented, except where specially agreed by the Classification Society, one tensile test is to be made from one piece unless the weight of finished material is greater than 50 tonnes or fraction thereof. Additionally tests are to be made for every variation of 10 mm in the thickness or diameter of products from the same cast.

13.2. Number of Impact Tests (except for Grades E, E32, E36, E 40, F32, F36 and F40), see Tables 8 &9.(i) Except where otherwise specified or specially agreed by the Classification Society, for each

batch presented, at least one set of three Charpy V-notch test specimens is to be made from one piece unless the weight of finished material is greater than 50 tonnes, in which case one extra set of three test specimens is to be made from a different piece from each 50 tonnes or fraction thereof. When steel plates except for Grade A steel over 50 mm in thickness issupplied in the controlled rolled condition, the frequency of impact test is to be made from adifferent piece from each 25 tonnes or fraction thereof.

(ii) When, subject to the special approval of the Classification Society, material is supplied in the as rolled condition, the frequency of impact tests is to be increased to one set from each batch of 25 tonnes or fraction thereof. Similarly Grade A steel over 50mm in thickness may besupplied in the as rolled condition. In such case one set of three Charpy V-notch testspecimens is to be taken from each batch of 50 tonnes or fraction thereof.

(iii) The piece selected for the preparation of the test specimens is to be the thickest in each batch.

W11cont’d

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▲

11-12

Fig. 4 H-sections Fig. 6 Bars;Fig. 5 Bulb flats

2/3

1/3 �� 1/3

�1/2

1/4

1/4

1/6 1/2 ��2/3 1/3

,IACS Req. 1979/Rev. 2 1995/Corr., v2.1

W11.13.3-W11.14.8

13.3 Number of Impact Tests (Grades E, E32, E36, E40, F32, F36 and F40)(i) For steel plates supplied in the normalised or TM condition one set of impact test specimens is

to be taken from each piece. For quenched and tempered steel plates one set of impact test specimens is to be taken from each length as heat treated.

(ii) For sections one set of impact tests is to be taken from each batch of 25 tonnes or fraction thereof.

(iii) When, subject to the special approval of the Classification Society, sections other than Grades E40 and F40 are supplied in the as rolled or controlled rolled condition, one set of impact tests is to be taken from each batch of 15 tonnes or fraction thereof.

(iv) For (ii) and (iii) above the piece selected for the preparation of the test specimens is to be the thickest in each batch.

14. Retest Procedures

14.1 When the tensile test from the first piece selected in accordance with W11.13.1 fails to meet the requirements, two further tensile tests may be made from the same piece. If both of these additional tests are satisfactory, this piece and the remaining pieces from the same batch may be accepted.

14.2 If one or both of the additional tests referred to above are unsatisfactory, the piece is to be rejected, but the remaining material from the same batch may be accepted provided that two of the remaining pieces in the batch selected in the same way, are tested with satisfactory results. If unsatisfactory results are obtained from either of these two pieces then the batch of material is to be rejected.

14.3 When the average value of the three initial Charpy V-notch impact specimens fails to meet the stated requirement, or the value for more than one specimen is below the required average value, or when the value of any one specimen is below 70% of the specified average value, three additional specimens from the same material may be tested and the results added to those previously obtained to form a new average. If this new average complies with the requirements and if not more than two individual results are lower than the required average and of these, not more than one result is below 70% of the specified average value the piece or batch may be accepted.

14.4 When the initial piece, representing a batch, gives unsatisfactory results from the additional Charpy V-notch impact tests referred to above, this piece is to be rejected but the remaining material in the batch may be accepted provided that two of the remaining pieces in the batch are tested with satisfactory results. If unsatisfactory results are obtained from either of these two pieces then the batch of material is to be rejected. The pieces selected for these additional tests are to be the thickest remaining in the batch.

14.5 If any test specimen fails because of faulty preparation, visible defects or (in the case of tensile test) because of fracturing outside the range permitted for the appropriate gauge length, the defective test piece may, at the Surveyors discretion, be disregarded and replayed by an additional test piece of the same type.

14.6 At the option of the steelmaker, when a batch of material is rejected, the remaining pieces in the batch may be resubmitted individually for test and those pieces which give satisfactory results may be accepted.

14.7 At the option of the steelmaker, rejected material may be resubmitted after heat treatment or re-heat treatment, or may be resubmitted as another grade of steel and may then be accepted provided the required tests are satisfactory.

14.8 In the event of any material proving unsatisfactory during subsequent working or fabrication, suchmaterial may be rejected, notwithstanding any previous satisfactory testing and/or certification.

W11cont’d

▲

▲

11-13

IACS Req. 1979/Rev. 2 1995, v2.1

W11.15-W11.16.2

15. Branding

15.1 Every finished piece is to be clearly marked by the maker in at least one place with the Classification Society's brand and the following particulars:

(i) Unified identification mark for the grade steel (e.g. A, A36).(ii) Steels which have been specially approved by the Classification Society and which differ

from these requirements (see W11.1.4) are to have the letter "S" after the above identification mark (e.g. A36S, ES).

(iii) When required by the Classification Society, material supplied in the thermo-mechanically controlled process condition is to have the letters TM added after the identification mark (e.g. E36 TM).

(iv) Name or initials to identify the steel works.(v) Cast or other number to identify the piece.(vi) If required by the purchaser, his order number or other identification mark.

15.2 The above particulars, but excluding the manufacturer's name or trade mark where this is embossed on finished products are to be encircled with paint or otherwise marked so as to be easily recognisable.

15.3 Where a number of light materials are securely fastened together in bundles the manufacturer may, subject to the agreement of the Classification Society, brand only the top piece of each bundle, or alternatively, a firmly fastened durable label containing the brand may be attached to each bundle.

15.4 In the event of any material bearing the Classification Society's brand failing to comply with the test requirements, the brand is to be unmistakably defaced by the manufacturer.

16. Documentation

16.1 The Surveyor is to be supplied with the number of copies as required by the Classification Society, of the test certificates or shipping statements for all accepted materials. The Classification Society may require separate documents of each grade of steel. These documents are to contain, in addition to the description, dimensions, etc, of the material, at least the following particulars:

(i) Purchaser's order number and if known the hull number for which the material is intended.(ii) Identification of the cast and piece including, where appropriate, the test specimen number.(iii) Identification of the steelworks.(iv) Identification of the grade of steel.(v) Ladle analysis (for elements specified in Tables 1 & 2).(vi) Condition of supply when other than as rolled i.e. normalised, controlled rolled or thermo-

mechanically rolled.(vii) State if rimming steel has been supplied for grade A sections, up to 12.5 mm thick.(viii) Test Results

16.2 Before the test certificates or shipping statements are signed by the Surveyor, the manufacturer is required to furnish him with a written declaration stating that the material has been made by an approved process and that it has been subjected to and has withstood satisfactory the required tests in the presence of the Surveyor or his authorized deputy. The name of the Classification Society is to appear on the test certificate. The following form of declaration will be accepted if stamped or printed on each test certificate or shipping statement with the name of the steelworks and initialled for the makers by an authorized official:

"We hereby certify that the material has been made by an approved process and has been satisfactorily tested in accordance with the Rules of the Classification Society."

W11cont’d

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▲

11-14

IACS Req. 1979/Rev. 2 1995, v2.1

W11cont’d

▲

W11.16

Table 8Required condition of supply and number of impact tests for normal strength steels

Remarks1. Condition of Supply

A – AnyN – Normalised ConditionCR – Controlled Rolled ConditionTM – Thermo-Mechanical rollingAR* – As Rolled Condition subject to special approval of the Classification SocietyCR* – Controlled Rolled Condition subject to special approval of the Classification Society

2. Number of Impact TestsOne set of impact tests is to be taken from each batch of the "specified weight" in ( ) or fraction thereof.

3. See Note (5) of Table 6.

Grade Deoxidation Products Condition of Supply (Batch for Impact Tests) (1)(2)Practice

Thickness (mm)10 12.5 20 25 30 35 40 50 100

A(-)Rimmed Sections Not applicable

AFor t ≤ 50mm N(-)

Any method Plates A(-) TM(-) (3)

except rimmed CR (50), AR* (50)For t > 50mmKilled

Sections A(-) Not applicable

For t ≤ 50mm N(50)Any method Plates A(-) A(50) TM(50)

B except rimmed CR (25), AR* (25)For t > 50mmKilled

Sections A(-) A(50) Not applicable

Killed PlatesSections A(50) Not applicable

N(50) N(50)Plates Plates A(50) CR(50) TM(50)Killed and fine TM(50) CR(25)

D grain treatedN(50)

A(50) CR(50) Not applicableSections TM(50)

AR*(25)

Plates N(Each piece)E Killed and fine TM(Each piece)

grain treatedN(25)

Sections TM(25) Not applicableAR* (15), CR*(15)

11-15

W11

W11cont’d

IACS Req. 1979/Rev.2 1995, v2.1

Table 9 Required condition of supply and number of impact tests for higher

Grain Condition of supply (Batch for Impact Tests (1)(2)

Grade Deoxidation Refining Products Thickness (mm)Practice Elements 10 12.5 20 25 30 35 40 50 100

N(50) N(50), CR(25), TM(50)Plates A(50) CR(50),TM(50)

Nb and/orV N(50)

Sections A(50) CR(50), TM(50) Not applicableA32 Killed and fine AR* (25) A36 grain treated

AR* (25) Not applicablePlates A(50) N(50), CR(50) N(50), CR(25), TM(50)

Al alone TM(50)or withTi N(50)

Sections A (50) CR(50) Not applicable

TM(50)

AR* (25)

N(50)A40 Killed and fine Any Plates A(50) CR(50) Not applicable

grain treated Sections TM(50)Plates A(50) N(50) N(50), CR(25), TM(50)

Nb and/or CR(50), TM(50)V N(50)

Sections A(50) CR(50), TM(50) Not applicable

D32 Killed and fine AR* (25)

D36 grain treatedPlates A(50) AR*(25) Not applicable

N(50), CR(50), TM (50) N(50), CR25, TM(50)Al aloneor with N(50)Ti Sections A(50) CR(50), TM(50) Not applicable

AR* (25)

N(50)

D40 Killed and fine Any Plates, CR(50) Not applicable

grain treated Sections TM(50)

Plates N(Each piece)TM(Each piece)

E32 Killed and fine AnyE36 grain treated N(25)

Sections TM(25) Not applicableAR* (15), CR* (15)

N(Each piece)Plates TM(Each piece) Not applicable

QT(Each length as heat treated)E40 Killed and fine Any

grain treated N(25)Sections TM(25)

QT(25) Not applicable

11-16

W11

W11cont’d

IACS Req. 1979/Rev. 2 1995, v2.1

Table 9 Required condition of supply and number of impact tests for higher strength steels (cont’d)

Remarks(1) Condition of Supply

A - AnyN - Normalized ConditionCR - Controlled Rolled Condition TM - Thermo-Mechanical RollingQT - Quenched and Tempered ConditionAR* - As Rolled Condition subject to the special approval of the Classification SocietyCR* - Controlled Rolled Condition subject to the special approval of the Classification Society

(2) Number of Impact TestsOne set of impact tests is to be taken from each batch of the “specified weight” in ( ) or fraction thereof.For grades A32 and A36 steels a relaxation in the number of impact tests may be permitted. (See Note(3) of Table 7.)

Grain Condition of supply (Batch for Impact Tests (1)(2)

Grade Deoxidation Refining Products Thickness (mm)Practice Elements 10 12.5 20 25 30 35 40 50 100

N(Each piece) Not applicablePlates TM(Each piece)

QT(Each length as heat treated)

F32 Killed and fine AnyF36 grain treated N(25)

Sections TM(25) Not applicableQT(25)CR*(15)

N(Each piece)Plates TM(Each piece) Not applicable

QT (Each length as heat treated)

F40 Killed and fine Anygrain treated N(25)

Sections TM(25) Not applicableQT(25)

11-17

Appendix : Schematic Diagrams of Thermo-Mechanical and Conventional Processes

Note:TM : Thermo-Mechanical Rolling (Thermo-Mechanical Controlled Process)AcC : Accelerated CoolingAR : As Rolled(*) : Sometimes rolling in the dual-phase temperature region of austenite and

ferriteN : NormalisingCR (NR) : Controlled Rolling (Normalising Rolling)R : Reduction

Note:These requirements were first adopted as UR.1 Requirements for Hull Structural Steels (1959) andUR.12 Requirements for High Tensile Hull Structural Steels (1971)These were subsequently revised to incorporate S1 units and were adopted asUR 128 Normal Strength Hull Structural Steel (1977) andUR 132 Requirements for High Tensile Hull Structural Steel (1977).

In 1979 these requirements were further revised and combined as UR 162 which was subsequently re-printed and issued as Unified Requirement W11.In 1994, these requirements were revised on the basis of the contents of W11. Normal and higher strength hull structural steelsW19. Normal and higher strength hull structural steel grades E and E36 with thickness above 50 up to100 mm.W20. Higher strength hull structural steels with a minimum yield strength of 390 N/mm2 and W21. Hull structural steels for low temperature application and reissued as Unified Requirement W11.

W11

W11cont’d

IACS Req. 1979/Rev. 2 1995, v2.1

Structure Temperature Thermo-Mechamical Processes

Type of Processing

Conventional Processes

TM AR N CR(NR)

Recrystallized Austenite

Non-recrystallized Austenite

Austenite + Ferrite

Austenite + Perlite orFerrite + Bainite

Normal Slab Heating Temp.

Normalizing Temp.

Ar3

Ar1 ��R

AcC

R(*)

R(*)

R(*)

RR

AcC

RRRRRRR

RRR

RRR

RR

▲▲

11-18

IACS Req. 1989/Rev. 3 1995

W13.1.1-W13.3.1

Allowable under thickness tolerances ofsteel plates and wide flats

W13.1 Scope

W13.1.1 These requirements apply to the allowable under thickness tolerances of steel plates and wideflats with thicknesses of 5 mm and over, covering the following steel grades:

(i) Normal and high strength hull structural steels according to W11, W19, W20 and W21.

(ii) Steels for machinery structures in accordance with the individual Rules of Classification Societies.

The allowable under thickness tolerances for thicknesses below 5 mm may be specially agreed.

W13.1.2 These requirements do not cover plates and wide flats intended for the construction ofboilers, pressure vessels and independent tanks, e.g. for the transportation of liquefied gases orchemicals.

NOTE:Tolerances for length, width, flatness and over thickness may be taken from national or internationalstandards.

W13.2 Manufacturers responsibility

W13.2.1 The responsibility for maintaining the required tolerances rests with the manufacturer, who isto carry out the necessary measurements. Occasional checking by the Surveyor does not absolve themanufacturer from this responsibility.

W13.3 Allowable under thickness tolerances

W13.3.1 The maximum permissible under thickness tolerance for hull structural plates and wide flatsfor both normal and high strength steels is -0,3mm.

Note:The attention of shipbuilders and shipowners is to be drawn to the fact that when thickness gauging iscarried out during the ship's life, estimation of the diminution of hull plating and structure will be basedon the nominal thickness, this being the original approved thickness for the item of structure underconsideration.

The under thickness tolerance acceptable for Classification is to be considered as the lower limit of a"plus-minus" range of thickness tolerance which could be found in the normal production of aconventional rolling mill manufacturing material, on average, to the nominal thickness.

With modern rolling mills, however, it may be possible to produce plates within a narrow range ofthickness tolerance thus permitting the consistent production of material having a thickness less than thenominal thickness whilst at the same time satisfying the under thickness tolerance given.

▲▲

W13(1981)(Rev. 11989)(Rev. 21992)(Rev. 31995)

▲

In such cases, the time for the material to reach the maximum allowable diminution may be reduced.

It is therefore a matter for the shipbuilder and shipowner to mutually agree in individual cases as towhether, for commercial reasons, they wish to specify a more stringent under thickness tolerance thanthat given.

W13.3.2 The tolerances for plates and wide flats for machinery structures are to be in accordance withTable 1.

Table 1

W13.4 Thickness measurements

W13.4.1 The thickness is to be measured at random locations whose distance from a longitudinal edgeshall be at least 10mm. Local surface depressions resulting from imperfections and ground areasresulting from the elimination of defects may be disregarded provided the imperfections or grinding is inaccordance with national or international standards.

W13(cont’d)

IACS Req. 1989/Rev. 3 1995

W13.3-W13.4

▲

Nominal thickness (mm) Under thickness tolerance (mm)

≥ 5 – < 8 – 0,4≥ 8 – < 15 – 0,5≥ 15 – < 25 – 0,6≥ 25 – < 40 – 0,8≥ 40 – 1,0

Steel plates and wide flats with improvedthrough thickness properties

W14.1 Scope

These requirements apply as a supplement to W11, normal and high strength structural steels for platesand wide flats with thickness ≥ 15 mm, where improved through thickness properties are specified.These requirements may also be applied for lower thicknesses at the discretion of the Society. Theserequirements may also be applied at the discretion of the individual Society as a supplement to othermaterial specifications.

W14.2 Requirements for the reduction of area

The minimum average value for the reduction of area of at least 3 tensile test specimens taken in thethrough thickness direction of the product must be 25%. Only one individual value may be below theminimum average value but not less than 20%.

W14.3 Tensile test

W14.3.1 Test sampling

Unless otherwise specified (see Note) the test sampling is to be performed as follows:

(a) Plates: One sample is to be taken from one end of each rolled length.(b) Wide flats: Products of the same cast, thickness and heat treatment are to be divided into batches

of 10t, or, where their thickness exceeds 25 mm, of 20t. From one piece of each batch at least one sample is to be taken.

The samples are to be cut from a position corresponding to the middle of the product as shown in Fig 1.

NOTE

In lieu of the above mentioned procedure the test sampling may be performed in accordance with anaccepted national or international standard.

IACS Req. 1982/v0.1

W14.1-W14.3

W14(1982)

▲

▲

Principal Rolling Direction

Fig. 1 Test Sampling

Center line of Product

Test Sample

/Top of ingot when applicable/

▲

W14.3.2-W14.6

W14.3.2 Dimension of test sample

The test sample must have a dimension sufficient for the preparation of 6 specimens. Generally 3 testspecimens are to be prepared while the rest of the sample remains for possible retests.

W14.3.3 Test specimens preparation

The test specimens are to be machined in accordance with a recognised standard to the followingdimensions:

Product 1/ Diameter of parallelthickness test specimen length

mm mm mm15 ≤ 25 do = 6 Lo ≥ 2 do

> 25 do = 10

1Product thicknesses below 15mm may be specially considered

Where the product thickness does not allow to prepare specimens of sufficient length suitable for thegripping jaws of the testing machine, the ends of the specimens may be built up by suitable weldingmethods. The welding must not impair the portion of the specimen within the parallel length.

W14.4 Retest procedure

If the average of the three test results is less than the specified value or if one individual result is less thanthe specified value, three more tests are carried out on the remaining test pieces. The average of theresults of the six tests shall be greater than the specified value and no individual result from the newseries shall be less than the specified value.

W14.5 Ultrasonic tests

Ultrasonic tests may be required if deemed necessary by the individual Society and may be performed inaccordance with an accepted standard.

W14.6 Marking

Products complying with these requirements are to be marked with the mark Z (or Z25) in addition to thematerial grade designation, e.g. EH36-Z25.

W14(cont’d)

IACS Req. 1982/v0.1

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W17.1

Approval of consumables for welding normaland higher strength hull structural steels1. General

1.1 Scope

1.1.1 These requirements give the conditions of approval and inspection of welding consumables usedfor hull structural steel welding as follows:

- normal strength steels Grades A, B, D and E ,- higher strength steels Grades A32, D32, E32, A36, D36 and E36,- higher strength steels with minimum yield strength 390 N/mm2: Grades A 40, D 40 and E40,- higher strength steels for low temperature application: Grades F 32, F 36 and F 40.

Welding consumables for high strength quenched and tempered steels for welded structures acc. to URW 16 are subject to special consideration by the individual Classification Society.

These requirements are not applicable for welding procedure qualification tests at the shipyard.

1.1.2 Categories of productsThe concerned welding consumables are divided into several categories as follows:

- covered electrodes for manual welding and gravity welding,- wire/flux combinations for two run or multirun submerged arc welding,- solid wire/gas combinations for arc welding,- flux cored wires with or without gas for arc welding,- consumables for use in electroslag and electrogas vertical welding

1.2 Grading

1.2.1 Basic groups and gradesFiller metals are divided into two groups:

- normal strength filler metals for welding normal strength hull structural steels, - higher strength filler metals for welding normal and higher strength hull structural

steels with minimum yield strength up to 355 N/mm2,- higher strength filler metals for welding normal and higher strength hull structural

steels with minimum yield strength up to 390 N/mm2. Each of the three groups is based on corresponding tensile strength requirements. Each filler metal group is further divided into several grades:

- Grades 1, 2 and 3 for ordinary-strength filler metals, - Grades 1Y, 2Y, 3Yand 4Y for higher strength filler metals for steels up to 355 N/mm2

yield strength,- Grades 2Y 40, 3 Y 40 and 4 Y 40 for higher strength filler metals for steels up to

390 N/mm2 yield strength.

The Grade assignment is given in respect of Charpy V-notch impact test requirements.

For each strength basic group, welding consumables, which have satisfied the requirements for a higher toughness grade are considered as complying with the requirements for a lowertoughness grade.

1.2.2 Correlation of welding consumables to hull structural steel gradesThe correlation between the hull steel grades and the welding consumables grades that must be used for the hull steel welding, is stated in the following Table 1:

W17(1986)(Rev.11993)

IACS Req. 1993

▲

NOTES:

(a) When joining normal to higher strength structural steel, consumables of the lowest acceptable grade for either material being joined may be used.

(b) When joining steels of the same strength level but of different toughness grade, consumables of the lowest acceptable grade for either material being joined may be used.

(c) It is recommended that controlled low hydrogen type consumables are to be usedwhenjoining higher strength structural steel to the same or lower strength level, except thatother consumables may be used at the discretion of the Society when the carbon equivalent isbelow or equal to 0.41%.When other than controlled low hydrogen type electrodes are usedappropriate procedure tests for hydrogen cracking may be conducted at the discretion of theSociety.

(d) The welding consumables approved for steel Grades A 40, D 40, E 40 and/or F 40 may alsobe used for welding of the corresponding grades of normal strength steels subject to thespecial agreement with the Classification Society

(e) When joining higher strength steels using Grade 1Y welding consumables, the material thicknesses should not exceed 25 mm.

1.2.3 Hydrogen marksWelding consumables of Grades 2 and 3 and Grades 2Y, 3Y and 4Y and of Grades 2Y 40, 3Y 40 and 4Y 40, for which the hydrogen content has been controlled in accordance with paragraph 4.5.3 are identified by the mark H15, H10 or H5.

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Grades of welding Hull structural steel grades

consumables (see notes) A B D E A32/36 D32/36 E32/36 F32/36 A40 D40 E40 F40

1, 1S. 1T, 1M, 1TM, IV X

1YS, 1YT, 1YM, 1YTM, 1YV X X2)

2, 2S, 2T, 2M, 2TM, 2V X X X

2Y, 2YS, 2YT,2YM, 2YTM, 2YV X X X X X

2Y40, 2Y40S, 2Y40T, 1) 1) 1) X X X X2Y40M, 2Y40TM, 2Y40V

3, 3S, 3T, 3M, 3TM, 3V X X X X

3Y, 3YS, 3YT, 3YM, 3YTM, 3YV X X X X X X X

3Y40, 3Y40S, 3Y40T 3Y40M, 3Y40TM, 3Y40V 1) 1) 1) 1) X X X X X X

4Y, 4YS, 4YT,4YM, 4YTM, 4YV X X X X X X X X

4Y40, 4Y40S, 4Y40T 4Y40M, 4Y40TM, 4Y40V 1) 1) 1) 1) X X X X X X X X

1) see note d)2) see note e)

Table 1 - Correlation of welding consumables to hull structural steels

W17.1

1.3 Manufacture

1.3.1 The manufacturer's plant, methods of production and quality control of welding consumables are to be such as to ensure reasonable uniformity in manufacture.

2. Approval procedure

2.1 Plant inspection

2.1.1 The Surveyor is to be satisfied that the manufacturer's plant, methods of production and quality control of welding consumables are to be such as to ensure a reasonable uniformity in manufacture, as mentioned in 1.3.1 above.

2.2 Test assemblies

2.2.1 PreparationThe test assemblies are to be prepared under the supervision of the Surveyor, and all tests are to be carried out in his presence.

When a welded joint is performed, the edges of the plates are to be bevelled either by mechanical machining or by oxygen cutting; in the later case, a descaling of the bevelled edges is necessary.

2.2.2 Welding conditionsThe welding conditions used such as amperage, voltage, travel speed, etc are to be within the rangerecommended by the manufacturer for normal good welding practice. Where a filler material is stated tobe suitable for both alternating current (AC) and direct current (DC), AC is to be used for the preparationof the test assemblies.

2.3 Firms with several factories - sister firms

When a filler product is manufactured in several factories of the same company, the complete series ofapproval tests should be carried out in one of the works only. In the other factories, a reduced testprogramme at least equivalent to annual tests is permitted if the manufacturer can certify that thematerials used and the fabrication process are identical with those used in the main works.This requirement is applicable to all manufacturers of filler products under license (sister firms).However, should there be any doubt, complete test-series may be required.

NOTE:Wire flux combination for submerged arc welding. If a unique powder flux is combined with differentwires coming from several factories belonging to the same firm, it may be admitted to perform only onetest-series if the different wires are conformable to the same technical specification, after approval of therelevant Classification Society.

2.4 Annual inspection and tests

The production techniques and associated quality control procedures at all establishments approved forthe manufacture of welding consumables are to be subjected to an annual re-appraisal. On theseoccasions, samples of the approved consumable are to be selected by the Surveyor and subjected to thetests detailed in subsequent sections of these Requirements. These are to be completed and reportedwithin the one year period beginning at the initial approval date, and repeated annually so as to provide atleast an average of one annual test per year. Equivalent alternative arrangements may be accepted subjectto special agreement with the Classification Society.

2.5 Alterations to approved consumables

Any alteration proposed by the manufacturer to the approved consumable which may result in a changein the chemical composition and the mechanical properties of the deposited metal, must be immediatelynotified to the Society. Additional tests may be necessary.

2.6 Upgrading and uprating

Upgrading and uprating of welding consumables will be considered only at manufacturer's request,preferably at the time of annual testing. Generally, for this purpose, tests from butt weld assemblies willbe required in addition to the normal annual approval tests.

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W17.1-W17.2

2.7 Additional tests

The classification societies may request, in a particular case, additional tests or requirements as may beconsidered necessary.

3. Mechanical testing procedure

3.1 Test specimens

3.1.1 Specimens dimensionsDeposited metal and butt weld tensile, butt weld bend and Charpy V-notch impact test specimens are to be machined to the dimensions given in UR W2.

3.1.2 Specimens location and preparation

.1 Deposited metal tensileThe longitudinal axis must coincide with the centre of the weld and:

(i) the mid thickness of the weld in the deposited metal test assemblies;(ii) the mid thickness of the 2nd run in the two-run welded test assemblies.

The specimens may be heated to a temperature not exceeding 250°C for a period not exceeding 16 hours for hydrogen removal prior to testing.

.2. Butt weld tensileThe upper and lower surfaces of the weld are to be filed, ground or machined flush with the surface of the plate.

.3 Butt weld bendThe upper and lower surfaces of the weld are to be filed, ground or machined flush with the Surface of the plate and the sharp corners of the specimens rounded to a radius not exceeding 2 mm.

.4 Charpy V-notch impactThe test specimens shall be cut with their longitudinal axes transverse to the weld length and:

(i) at mid thickness of the weld in the deposit metal and butt weld test assemblies with multirun technique;

(ii) on the 2nd run side, 2 mm maximum below the surface in the two-run welded test assemblies;

(iii) 2 mm maximum below one surface in the electroslag or electrogas welded test assemblies.

The notch shall be cut in the face of the test piece perpendicular to the surface of the plate and shall bepositioned in the centre of the weld and, for electroslag and electrogas welded test assemblies, also at 2mm from the fusion line in the deposited metal.

3.2 Testing procedures

3.2.1 TensileTensile tests are to be carried out on an approved tensile testing machine.On deposited metal test specimens, the values of yield stress, tensile strength and elongation are to berecorded. On butt weld specimens, the values of tensile strength are to be recorded together with theposition of fracture.

3.2.2 BendThe test specimens are to be capable of withstanding, without fracture or crack, being bent through anangle of 120° over a former having a diameter three times the thickness of the specimen.However, superficial cracks of less than 3 mm long on the outer surface should not be taken intoconsideration.

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W17.2 - W17.3

▲

For each set of bend tests one specimen is to be tested with the face of the weld in tension and the otherwith the root of the weld in tension except in the electroslag or electrogas welded test assemblies, whereside bend tests are carried out in lieu of face and root bend tests.

3.2.3 Charpy V-notch impactImpact tests are to be carried out on a Charpy impact machine of an approved type.

A set of three test specimens is to be prepared and tested. The average absorbed energy value is to complywith the requirements of subsequent sections. One individual value may be less than the required averagevalue provided that it is not less than 70% of this value.

The test temperature for Grades 2, 2Y, 2Y 40, 3, 3Y, 3Y 40, 4Y and 4Y 40 test pieces is to be controlledto within ±2°C of the prescribed temperature.

3.3 Re-test procedures

3.3.1 Tensile and bendWhere the result of a tensile or bend test does not comply with the requirements, duplicate test specimensof the same type are to be prepared and satisfactorily tested. Where insufficient original welded assemblyis available, a new assembly is to be prepared using welding consumables from the same batch. If the newassembly is made with the same procedure (particularly the number of runs) as the original assembly, onlythe duplicate re-test specimens needs to be prepared and tested. Otherwise, all test specimens should beprepared as for re-testing.

3.3.2 Charpy V-notch impactWhere the results from a set of three impact test specimens do not comply with the requirements, anadditional set of three impact test specimens may be taken provided that not more than two individualvalues are less than the required average value and, of these, not more than one is less than 70 percent ofthis average value. The results obtained are to be combined with the original results to form a new averagewhich, for acceptance, is to be not less than the required value. Additionally, for these combined resultsnot more than two individual values are to be less than the required average value, and of these, not morethan one is to be less than 70 per cent of the average value. Further re-tests may be made at the Surveyor'sdiscretion, but these must be made on a new welded assembly and must include all tests required for theoriginal assembly, even those which were previously satisfactory.

4. Covered electrodes for manual arc welding

4.1 General

4.1.1 Grades Depending on the results of the Charpy V-notch impact tests, electrodes are divided into the followinggrades:- for normal strength steel: Grades 1, 2 and 3- for higher strength steel with minimum yield strength up to 355 N/mm2: Grades 2Y and 3Y and

4Y (Grade 1Y not applicable for manual welding).- for higher strength steels with minimum yield strength up to 390 N/mm2: Grades 2Y 40, 3Y40,

and 4Y 40.

4.1.2 Hydrogen marksIf the electrodes are in compliance with the requirements of the hydrogen test given in 4.5 hereafter, asuffix H15, H10 or H5 will be added to the Grade mark.

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W17.3 - W17.4

4.2 Deposited metal tests

4.2.1 Preparation of deposited metal test assembliesTwo deposited metal test assemblies are to be prepared in the downhand position as shown in Fig 4.1,one with 4 mm diameter electrodes and the other with the largest size manufactured. If an electrode isavailable in one diameter only, one test assembly is sufficient. Any grade of ship structural steel may beused for the preparation of these test assemblies.

Figure 4.1 Deposited metal test assembly

The weld metal is to be deposited in single or multi-run layers according to normal practice, and thedirection of deposition of each layer is to alternate from each end of the plate, each run of weld metalbeing not less than 2 mm and not more than 4 mm thick. Between each run, the assembly is to be left instill air until it has cooled to less than 250°C but not below 100°C, the temperature being taken in thecentre of the weld, on the surface of the seam. After welding, the test assemblies are not to be subjectedto any heat treatment.

4.2.2 Chemical analysisAt the discretion of each individual Society, the chemical analysis of the deposited weld metal in eachtest assembly is to be supplied by the manufacturer and is to include the content of all significant alloyingelement.

4.2.3 Execution of testsOne tensile and three impact test specimens are to be taken from each test assembly as shown in Figure4.1. Care is to be taken that the axis of the tensile test specimen coincides with the centre of the weld andthe mid-thickness of the plates. Tests are to be performed according to Section 3 of these requirements.

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All dimensions in mm unless otherwise indicated

80°

Min 100 Min 100

80°

16min

10

30

Min 20

Line of cut for tensile specimen

1 tensile

3 Charpy test pieces taken at

mid-depth of weld Charpy notch at right angles to surface of plate

20

▲W17.4

4.2.4 Results of tests and requirementsThe results of all tests are to comply with the requirements of Table 4a as appropriate.

Table 4a Requirements for deposited metal tests (covered manual electrodes)

4.3 Butt weld tests

4.3.1 Preparation of butt weld test assembliesButt weld assemblies as shown in Fig 4.2 are to be prepared for each welding position (downhand,horizontal-vertical, vertical-upward, vertical-downward and overhead) for which the electrode isrecommended by the manufacturer, except that electrodes satisfying the requirements for downhand andvertical-upward positions will be considered as also complying with the requirements for the horizontal-vertical position subject to the agreement of the Classification Society.

Where the electrode is to be approved only in the downhand position, an additional test assembly is to beprepared in that position.

For the preparation of the test assemblies one of the steel grades as listed below for the individualelectrode grades shall be used:

- Grade 1 electrodes : A- Grade 2 electrodes : A, B, D- Grade 3 electrodes : A, B, D, E- Grade 2Y electrodes : A32, A36, D32, D36- Grade 3Y electrodes : A 32, A 36, D32, D36, E32, E36.- Grade 4Y electrodes : A32, A36, D 32, D 36, E 32, E 36, F 32, F 36- Grade 2Y 40 electrodes : A 40, D 40- Grade 3Y 40 electrodes : A 40, D 40, E 40- Grade 4Y 40 electrodes : A 40, D 40, E 40, F 40

Where higher strength steel with minimum yield strength 315 N/mm2 is used for grade 2Y, 3Y and 4Yelectrodes, the actual tensile strength of the steel is to be not less than 490 N/mm2. The chemicalcomposition including the content of grain refining elements is to be reported.

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Charpy V-notch impact tests

Elongation onYield stress Tensile 50 mm gauge length Test Average

Grade N/mm2 Strength (Lo = 5 d) Temperature Energy

minimum N/mm2 % minimum oC J minimum

1 20 472 305 400 - 560 22 0 473 -20 47

2Y 0 473Y 375 490 - 660 22 -20 474Y -40 47

2Y 40 0 473Y 40 400 510 - 690 22 -20 474Y 40 -40 47

W17.4

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30

50

30°

Discard

Discard

Root bend

Face bend

Transverse tensile

Charpy V-notch test piece from downhand

and venicaI test assemblies

55

30°

15-20

Min 100 Min 100

30

2-3


Figure 4.2 Butt weld test assembly

W17.4

4.3.2 Sequence of weldingThe following welding procedure is to be adopted in making test assemblies:

Downhand (a). The first run with 4 mm diameter electrode. Remaining runs (except the last two layers)with 5 mm diameter electrodes or above according to the normal welding practice with the electrodes.The runs of the last two layers with the largest diameter of electrode manufactured.

Downhand (b). (Where a second downhand test is required). First run with 4 mm diameter electrode.Next run with an electrode of intermediate diameter of 5 mm or 6 mm, and the remaining runs with thelargest diameter of electrode manufactured.

Horizontal-vertical. First run with 4 mm or 5 mm diameter electrode. Subsequent runs with 5 mmdiameter electrodes.

Vertical-upward and overhead. First run with 3.25 mm diameter electrode. Remaining runs with 4 mmdiameter electrodes or possibly with 5 mm if this is recommended by the manufacturer for the positionsconcerned.

Vertical-downward. If the electrode tested is intended for vertical welding in the downward direction,this technique is to be adopted for the preparation of the test assembly using electrode diameters asrecommended by the manufacturer.

For all assemblies the back sealing runs are to be made with 4 mm diameter electrodes in the weldingposition appropriate to each test sample, after cutting out the root run to clean metal. For electrodes suitablefor downhand welding only, the test assemblies may be turned over to carry out the back sealing run.

Normal welding practice is to be used, and between each run the assembly is to be left in still air until it hascooled to less than 250°C but not below 100°C, the temperature being taken in the centre of the weld, on thesurface of the seam. After welding, the test assemblies are not to be subjected to any heat treatment.

4.3.3 Radiographic examinationIt is recommended that the welded assemblies be subjected to a radiographic examination to ascertain ifthere are any defects in the weld prior to the preparation of test specimens.

4.3.4 Execution of testsThe test specimens as shown in Figure 4.2 are to be prepared from each test assembly. Tests are to beperformed according to Section 3 requirements.

4.3.5 Result of tests and requirementsThe results of all tensile and impact tests are to comply with the requirements of table 4b as appropriate.The position of fracture in the transverse tensile test is to be reported. The bend test specimens can beconsidered as complying with the requirements if, after bending, no crack or defect having anydimensions exceeding 3 mm can be seen on the outer surface of the test specimen.

Table 4b Requirements for butt weld test (covered manual electrodes)

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Average energy - J minimum

Tensile strength Test Downhand, VerticalGrade (transverse test) Temperature horizontal-vertical, (upward and

N/mm2 oC overhead downward)

1 20 47 342 400 0 47 343 -20 47 34

2Y 0 47 343Y 490 -20 47 344Y -40 47 34

2Y 40 0 47 413Y 40 510 -20 47 414Y 40 -40 47 41

W17.4

4.4 Hot cracking test

4.4.1 Hot cracking test may be required at the discretion of each individual Society.

4.5 Hydrogen test

4.5.1 Hydrogen marksAt the request of the manufacturer, electrodes may be submitted to a hydrogen test. A suffix H15, H10 orH 5 will be added to the grade number to indicate compliance with the requirements of this test.

4.5.2 Execution of hydrogen testThe mercury method as specified in the Standard ISO 3690-1977, or any method such as the gaschromatographic method which correlates with that method, must be used. The use of the glycerinemethod may be admitted at the Classification Society discretion. This method is described hereafter.

Four test specimens are to be prepared, measuring 12 mm by 25 mm in cross section by about 125 mm inlength. The parent metal may be any grade of ship structural steel and, before welding, the specimens areto be weighed to the nearest 0.1 gram. On the 25 mm surface of each test specimen, a single bead ofwelding is to be deposited, about 100 mm in length by a 4 mm electrode, fusing 150 mm of the electrode.The welding is to be carried out with an arc as short as possible and with a current of about 150 amp.

The electrodes, prior to welding, can be submitted to the normal drying process recommended by themanufacturer. Within 30 seconds of the completion of the welding of each specimen the slag is to beremoved and the specimen quenched in water at approximately 20°C.

After 30 seconds in the water, the specimen is to be cleaned and dried, and then placed in an apparatus suitablefor the collection of hydrogen by displacement of glycerine. The glycerine is to be kept at a temperature of45°C during the test. All four specimens are to be welded and placed in individual hydrogen collectingapparatus within a period of time which will limit any variation in hydrogen content due to variation inexposure to moisture absorption following any drying treatment. This should not exceed 30 minutes.

The specimens are to be kept immersed in the glycerine for a period of 48 hours and, after removal, are tobe cleaned in water and spirit dried and weighed to the nearest 0.1 gram to determine the amount of welddeposit. The amount of gas involved is to be measured to the nearest 0.05 cm3 and corrected fortemperature and pressure to 0°C and 760 mm Hg.

4.5.3 Results to be obtainedThe individual and average diffusible hydrogen contents of the four specimens are to be reported, and theaverage value in cm3 per 100 grams is not to exceed the following:

NOTE:For H5 mark only the mercury method is to be used.

4.6 Covered electrodes for manual fillet welding

4.6.1 GeneralWhere an electrode is submitted only to approval for fillet welding and to which the butt weld test provided in4.3 is not considered applicable, the first approval tests are to consist of the fillet weld tests given in 4.6.2, anddeposited metal tests similar to those indicated in 4.2. Where an electrode is submitted to approval for bothbutt and fillet welding, the first approval tests may, at the discretion of the Classification Society, include onefillet weld test as detailed hereunder and welded in the horizontal-vertical position.

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Mark Mercury Method(ISO 3690 - 1977)

H 15 15 1)

H 10 10 2)

H 5 5

1) 10 cm3 per 100 grams where the glycerine method is used

2) 5 cm3 per 100 grams where the glycerine method is used

W17.4

4.6.2 Fillet weld test assembliesWhen the electrode is proposed only for fillet welding, fillet weld assemblies as shown in figure 4.3,are to be prepared for each welding position (horizontal-vertical, vertical upwards, vertical downwards oroverhead) for which the electrode is recommended by the manufacturer. The length of the test assembliesL is to be sufficient to allow at least the deposition of the entire length of the electrode being tested.

The grade of steel used for the test assemblies is to be as detailed in 4.3.1.

The first side is to be welded using the maximum size of electrode manufactired and the second side is tobe welded using the minimum size of electrode manufactured and recommended for fillet welding.

The fillet size will in general be determined by the electrode size and the welding current employedduring testing.

4.6.3 Tests on fillet weld assemblies

.1 MacrographsEach test assembly is to be sectioned to form three macro-sections each about 25mm thick. They are tobe examined for root penetration, satisfactory profile, freedom from cracking and reasonable freedomfrom porosities and slag inclusions.

.2 HardnessAt the discretion of each Classification Society, the hardness of the weld, of the heat affected zone(HAZ) and of parent metal may be determined, and reported for information (see figure 4.4).

.3 FractureOne of the remaining sections of the fillet weld is to have the weld on the first side gouged or machinedto facilitate breaking the fillet weld, on the second side by closing the two plates together, submitting theroot of the weld to tension. On the other remaining section, the weld on the second side is to be gougedor machined and the section fractured using the same procedure. The fractured surfaces are to beexamined and there should be no evidence of incomplete penetration, or internal cracking and theyshould be reasonably free from porosity.

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g y

~ 150

20 25 25 25

L

~ 150

20

5050

~ 1/2 L ~ 1/2 L

20

20

Base metal

Hardness readings

Base metalHAZ

Figure 4.3 Fillet weld test assembly

Figure 4.4 Hardness readings

W17.4

4.7 Covered electrodes for gravity or contact welding

Where an electrode is submitted solely to approval for use in contact welding using automatic gravity orsimilar welding devices, deposited metal tests, fillet weld tests (see 4-6) and, where appropriate, but weldtests similar to those for normal manual electrodes are to be carried out using the process for which theelectrode is recommended by the manufacturer.

Where a covered electrode is submitted to approval for use in contact welding using automatic gravity orsimilar welding devices in addition to normal manual welding, fillet weld and, where appropriate, buttweld tests, using the gravity of other contact device as recommended by the manufacturer, are to becarried out in addition to the normal approval tests.

In the case of a fillet welding electrode using automatic gravity or similar contact welding devices, thefillet welding should be carried out using the welding process recommended by the manufacturer, withthe longest size of the electrode manufactured. The manufacturer's recommended current range is to bereported for each electrode size.

Where approval is requested for the welding of both normal strength and higher strength steel, theassemblies are to be prepared using higher strength steel.

4.8 Annual tests and upgrading

4.8.1 Annual tests and periodical inspection of manufacturer's plantAll establishments where approved electrodes are manufactured shall be subject to annual inspection.

The annual tests are to consist of at least the following:

.1 Covered electrode for normal manual arc weldingTwo deposited metal test assemblies are to be prepared in accordance with 4.2. The mechanicalproperties (one tensile test, 3 Charpy-V impact tests on each assembly) are to be in accordance with Table4.a. This also applies to electrodes which are approved only for fillet welding.

At the discretion of the Society a butt weld test to be welded in down-hand or in vertical position, can berequired in lieu of the deposited metal test 4 mm electrodes. Three Charpy V-notch impact test specimensare to be taken from the butt weld assembly.For Mark H 10 and Mark H 5 covered electrodes, an hydrogen test following 4.5 can also be required foreach annual test at the discretion of the Society.

.2 Covered electrodes for gravity or contact weldingWhere an electrode is approved solely for gravity or contact welding, the annual test is to consist of onedeposited metal test assembly using the gravity or other contact device as recommended by themanufacturer. If this electrode is approved also for normal manual arc welding the annual test is to beperformed according to 4.8.1.1.

4.8.2 Upgrading and uprating of electrodes

.1 Upgrading and uprating will be considered only at the manufacturer's request, preferably at thetime of annual testing. Generally, for this purpose, tests on butt-weld assemblies will be required inaddition to the normal reapproval tests.

.2 Upgrading refers to notch toughness and consequently, only Charpy V impact tests are requiredfrom the respective butt-weld assemblies as required by 4-3 (downhand, horizontal vertical, vertical upor/and down, overhead, as applicable), and have to be performed at the upgraded temperature.

These butt-weld tests are to be made in addition to the normal requirements for annual deposited metal tests(which have, of course, to take into consideration the upgraded temperature for Charpy V specimens).

.3 Uprating refers to the extension of approval in order to cover the welding of higher strength steels; ofcourse, welding of normal strength steels continue to be covered by the extended approval, as stated in 1.2.1.

For this purpose all butt-weld tests are to be made again, as required in 4.3 and using higher strengthsteel, as parent metal.

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W17.5

5. Wire flux combinations for submerged arc welding

5.1 General

5.1.1 CategoriesWire flux combinations for single electrode submerged arc automatic welding are divided into thefollowing two categories:– For use with the multi-run technique– For use with the two run technique

Where particular wire-flux combinations are intended for welding with both techniques, tests are to becarried out for each technique.

5.1.2 GradesDepending on the results of impact tests, wire-flux combinations are divided into the following grades:

– For normal strength steel: Grades 1, 2 or 3– For higher strength steels with minimum yield strength up to 355 N/mm2: Grades 1Y, 2Y, 3Y or

4Y.- for higher strength steels with minimum yield strength up to 390 N/mm2: Grades 2Y 40, 3Y 40 or

4Y 40.

The suffixes T, M or TM will be added after the grade mark to indicate approval for the two-runtechnique, multi-run technique or both techniques, respectively.

5.1.3 Multiple electrode submerged arc weldingWire-flux combinations for multiple electrode submerged arc welding will be subject to separateapproval tests. They are to be carried out generally in accordance with the requirements of this section.

5.1.4 Mechanical tests on assembliesMechanical tests on assemblies with submerged arc welding for wire/flux approval are given in Table5a.

5.2 Approval tests for multi run technique

5.2.1 Grades of steelWhere approval for use with the multi run technique is requested, deposited metal and butt weld tests areto be carried out.For deposited metal test assembly any grade of ship structural steel may be used.For butt weld test assembly one of the grades of steel as listed below for the individual grades of wire-flux combinations shall be used:

- Grade 1 wire-flux combinations : A- Grade 2 wire-flux combinations : A, B, D- Grade 3 wire-flux combinations : A, B, D, E- Grade 1 Y wire-flux combinations : A 32, A 36- Grade 2 Y wire-flux combinations : A32, A 36, D 32, D 36- Grade 3 Y wire-flux combinations : A32, A 36, D 32, D 36, E 32, E 36- Grade 4 Y wire-flux combinations : A32, A 36, D 32, D 36, E 32, E 36, F 32, F 36- Grade 2 Y 40 wire-flux combinations : A40, D 40- Grade 3 Y 40 wire-flux combinations : A40, D 40 E 40- Grade 4 Y 40 wire-flux combinations : A40, D 40, E 40, F 40

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W17.5

5.2.2 Deposited metal test assembly

.1 PreparationOne deposited metal test assembly is to be prepared as shown in Figure 5.1.

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30

TensileLine of cut

Impact

30

10101010

10

Tensile

Tensile

Tack weld


50

16

12

10°

20

200


Figure 5.1

W17.5

Table 5a General table giving the mechanical tests on assemblies with submerged arc welding for wire/flux approval

Symbol Definition: TT: Transverse Tensile Test on the butt weld assemblyTB : Transverse Bend Test on the butt weld assemblyCV : Charpy-V Impact Test in the axis of the weldLT : Longitudinal Tensile Test in the weld

Welding is to be carried out in the downhand position, and the direction of deposition of each run is to alternate from each end of the plate. After completion of each run, the flux and welding slag is to be removed. Between each run the assembly is to be left in still air until it has cooled to less than 250 °C, but not below 100 °C, the temperature being taken in the centre of the weld, on the surface of the seam. The thickness of the layer is to be not less than the diameter of the wire nor less than 4 mm.

The weld conditions, including amperage, voltage and rate of travel speed are to be in accordance with the recommendations of the manufacturer and are to conform with normal good welding practice for multi-run welding.

.2 Chemical analysisAt the discretion of each individual Society, the chemical analysis of the deposited weld metal in this testassembly is to be supplied by the manufacturer and is to include the content of all significant alloyingelements.

.3 Execution of testsIn accordance with Table 5a, the test specimens as shown in Figure 5.1 are to be prepared from each testassembly. Tests are to be performed according to Section 3 requirements.

.4 Results and requirementsThe results of all tests are to comply with the requirements of Table 5b, as appropriate.

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M T TM(multi-run technique) (two-run technique) two-run and multi-run technique)

Butt Weld AssemblyButt weld Butt weld Two-run technique

Deposited Butt weld assembly assembly Depositedmetal assembly (minimum (maximum metal Multi-run (Minimum (Maximumassembly thickness) thickness) assembly technique thickness) thickness)

2 TT 2 TT 2 TT 2 TT 2 TT 2 TT4 TB 2 TB 2 TB 4 TB 2 TB 2 TB

3 CV 3 CV 3 CV 3 CV 3 CV 3 CV 3 CV 3 CV2 LT 1 LT 1 LT 1 LT

W17.5

Table 5b Requirements for deposited metal tests (wire-flux combinations)

5.2.3 Butt Weld Test Assembly

.1 PreparationOne butt weld test assembly is to be prepared as shown in Figure 5.2 in the downhand position bywelding together two plates (20 to 25 mm thick), each not less than 150 mm in width and sufficientlength to allow the cutting out of test specimens of the prescribed number and size.

The plate edges are to be prepared to form a single vee joint, the included angle between the fusion facesbeing 60° and the root face being 4 mm.

The welding is to be carried out by the multi-run technique and the welding conditions are to be the sameas those adopted for the deposited metal test assembly.

The back sealing run is to be applied in the downhand position after cutting out the root run to clean metal.

After welding the test assembly is not to be subject to any heat treatment.

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Elongation onYield stress Tensile 50 mm gauge length Test Average

Grade N/mm2 Strength (Lo = 5 d) Temperature Energy

minimum N/mm2 % minimum oC J minimum

1 20 342 305 400 - 560 22 0 343 -20 34

1Y 20 342Y 0 343Y 375 490 - 660 22 -20 344Y -40 34

2Y 40 0 413Y 40 400 510 - 690 22 -20 41

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Figure 5.2 Multi-run butt weld test assembly (submerged arc welding)

.2 Radiographic examinationIt is recommended that the welded assembly be subject to a radiographic examination to ascertain if thereare any defects in the weld prior to the preparation of test specimens.

.3 Execution of testsThe test specimen to be prepared from the welded assembly are given in Table 5a and shown in Fig. 5.2.The tests are to be performed according to the requirements of Section 3.

.4 Results of tests and requirements The results of all tensile and impact tests are to comply with the requirements of Table 5c as appropriate.The position of the fracture in the transverse tensile test is to be reported.

The bend test specimens can be considered as complying with the requirements if, after bending, nocrack or defect, having any dimension exceeding 3 mm can be seen on the outer surface of the testspecimen.

Tensile

Bend

Bend

Bend

Bend

Tensile

Impact

Discard

60°

4

50

30

30

30

30

50

Discard

10

10

10


150 mm 150 mm

20

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Table 5c Requirements for butt weld tests (wire-flux combinations)

5.3 Approval tests for two run techniques

5.3.1 Number of test assembliesWhere approval for use with the two-run technique is requested, two butt weld test assemblies are to beprepared using the following thicknesses:

– For grades 1 and 1Y: 12 to 15 mm and 20 to 25 mm– For Grades 2, 2Y, 3, 3Y and 4Y: 20 to 25 mm and 30 to 35 mmfor Grades 2Y 40, 3Y 40 and 4Y 40: 20 to 25 mm and 30 to 35 mm

A limitation of the approval to the medium range (up to the maximum welded plate thickness) may beagreed to by the Society. Test assemblies shall then be welded using plates of 12 to 15mm and 20 to25mm irrespective of the grade for which the approval is requested..

When a wire-flux combination is offered to approval for use with the two-run technique only, it isreminded that no deposited metal test assemblies have to be done. In this case approval tests are limitedto the butt welds on two-run assemblies described in 5.3.2 hereafter.

Where approval is requested for welding of both normal strength and higher strength steel twoassemblies are to be prepared using higher strength steel. Two assemblies prepared using normal strengthsteel may also be required at the discretion of each Classification Society.

5.3.2 Butt weld test assemblies

.1 Preparation of assembliesThe maximum diameter of wire, grades of steel plate and edge preparation to be used are to be inaccordance with Fig. 5.3. Small deviations in the edge preparation may be allowed if requested by themanufacturer. The root gap should not exceed 1 mm.

Each butt weld is to be welded in two runs, one from each side, using amperages, voltages and travelspeeds in accordance with the recommendations of manufacturer and normal good welding practice.

After completion of the first run, the flux and welding slag are to be removed and the assembly is to beleft in still air until it has cooled to 100°C, the temperature being taken in the centre of the weld, on thesurface of the seam.

After welding, the test assemblies are not to be subjected to any heat treatment.

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Grade Tensile strength Test temperature Average energy

(transverse test) oC J minimum1 20 342 400 0 343 -20 34

1Y 20 342Y 0 343Y 490 -20 344Y -40 34

2Y40 0 413Y40 510 -20 414Y40 -40 41

▲

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Figure 5.3 Butt weld test assemblies (two-run technique)

.2 Radiographic examination

It is recommended that the welded assemblies are subjected to radiographic examination to

ascertain if there are any defects in the weld prior to the preparation of test specimens.

.3 Execution of tests

The test specimens indicated in Table 5a and shown in Figure 5.4 are to be prepared from each test

assembly. Tests are to be performed according to Section 3 requirements. The Charpy V-notch

impact test specimens are to be machined from each welded assembly from the positions and with

the orientations shown in Fig. 5.5.

Platethickness

[mm]

Recommendedpreparation

[mm]

Maximumdiameterof wire[mm]

Grade ofwire-flux

combination

Grade ofnormalstrength

steel

Grade ofhigher

strengthsteel

about12 – 15

about20 – 25

about30 – 35

5

1

1 Y

A

–

–

A 32,A 36

6

7

11 Y

22 Y

2 Y 40

3

3 Y

3 Y 40

4 Y

4 Y 40

A–

A, B or D–

–

A, B, D orE

–

–

–

–

–A 32, A 36

–A 32, A 36, D 32, D 36

A 40, D 40

– A 32, A 36, D 32,D 36, E 32, E 36

A 40, D 40, E 40A 32, A 36, D 32, D 36,E 32, E 36, F 32, F 36A 40, D 40, E 40, F 40

22 Y

2 Y 40

3

3 Y

3 Y 40

4 Y

4 Y 40

A, B or D–

–

A, B, D orE

–

–

–

–

–A 32, A 36, D 32, D 36

A 40, D 40

–

A 32, A 36, D 32,D 36, E 32, E 36

A 40, D 40, E 40

A 32, A 36, D 32, D 36,E 32, E 36, F 32, F 36

A 40, D 40, E 40, F 40

60o

8–12

70o

70o

6–14

▲

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{

min. 150 min. 150

T e n s i l e S p e c i m e n

B e n d S p e c i m e n




T e n s i l e S p e c i m e n

I m p a c t S p e c i m e n

30

30

50

50

30

30 mm for plates up to 25 mm thickness10

10

10

Longitudinal tensile (cylindrical specimen)


Figure 5.4��2nd run2 max.10


Figure 5.5

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.4 Results of tests and requirements

The results of all tensile and impact tests are to comply with the requirements of table 5b and 5c asappropriate. The position of fracture in the transverse tensile test is to be reported. The bend testspecimens can be considered as complying with the requirements if, after bending, no crack or defecthaving any dimensions exceeding 3 mm can be seen on the outer surface of the test speciment.

.5 Chemical analysis

The chemical analysis of the weld metal is to be supplied by the manufacturer, and is to include thecontent of all significant alloying elements.

5.4 Annual tests - upgrading

5.4.1 Annual testsAll establishments where approved wire/flux combinations are manufactured shall be subject to annualinspection.

Annual tests are to consist of at least the following:

a) multirun technique: on deposited metal assembly and tests: 1 tensile and 3 impact tests.b) two-run technique: one butt weld assembly with 20 mm minimum thickness plate and tests: 1

transverse tensile, 2 transverse bends and 3 impact tests. One longitudinal tensile test specimen is also to be prepared where the wire-flux combination is approved solely for the two-run technique.

The assemblies are to be prepared and tested in accordance with the requirements for initial approval.

Where a wire-flux combination is approved for welding both normal strength and higher strength steel,the latter steel is to be used for the preparation of the butt weld assembly required by 5.4.1 b).

5.4.2 Upgrading and rating

5.4.2.1 Upgrading of wire-flux combinations in connection with the impact properties will be consideredas detailed in 4.8.2.2, and for wire-flux combinations approved for two runs welding, a butt-weld in the maximum thickness approved is to be made and sampled for Charpy-V testing in accordance with 5.3.2.3.

5.4.2.2 Uprating of wire-flux combinations in connection with the tensile properties will be considered asdetailed in 4.6.2.3.

6. Wires and wire-gas combinations for metal arc welding

6.1 General

6.1.1 CategoriesWire-gas combinations and flux-cored or flux-coated wires (for use with or without a shielding gas) aredivided into the following categories for the purposes of approval testing:

a) For use in semi-automatic mulitrun welding.b) For use in single electrode automatic multirun welding.c) For use in single electrode automatic two-run welding.

NOTE:The term semi-automatic is used to describe processes in which the weld is made manually by a welderholding a gun through which the electrode wire is continuously fed.

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6.1.2 Grades and suffixes

.1 Depending on the results of impact tests, wires and wire-gas combinations are divided into the following grades:– For normal strength steel Grades 1, 2 and 3;– For higher strength steels with minimum yield strength up to 355 N/mm2: Grades 1Y, 2Y,

3Y and 4Y.- for higher strength steems with minimum yield strength up to 390 N/mm2: Grades 2Y 40, 3Y

40, and 4Y 40

.2 A suffix "S" will be added after the grade mark to indicate approval for semi-automatic multirun welding.

.3 For wires intended for automatic welding, the suffixes "T", "M" or "TM" will be added after the grade mark to indicate approval for two-run, multirun, or both welding techniques, respectively.

.4 For wires intended for both semi-automatic and automatic welding, the suffixes will be added in combination.

6.1.3 Composition of shielding gas

.1 Where applicable, the composition of the shielding gas is to be reported. Unless otherwise agreedby the Society, additional approval tests are required when a shielding gas is used other than that used forthe original approval tests.

.2 The approval of a wire in combination with any particular gas can be applied or transferred to anycombination of the same wire and any gas in the same numbered group as defined in Table 6a, subject tothe agreement of the Classification Society.

Table 6a Compositional limits of designated groups of gas types and mixtures.

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Group Gas composition (Vol. %)CO2 O2 H2 Ar

M1 1 > 0 to 5 - > 0 to 5 Rest 1) 2)2 > 0 to 5 - - Rest 1) 2)3 - > 0 to 3 - Rest 1) 2)4 > 0 to 5 > 0 to 3 - Rest 1) 2)

M2 1 > 5 to 25 - - Rest 1) 2)2 - > 3 to 10 - Rest 1) 2)3 > 5 to 25 > 0 to 8 - Rest 1) 2)

M3 1 >25 to 50 - - Rest 1) 2)2 - > 10 to 15 - Rest 1) 2)3 > 5 to 50 > 8 to 15 - Rest 1) 2)

C 1 100 - - -2 Rest > 0 to 30 - -

1) Argon may be substituted by Helium up to 95% of the Argon content.2) Approval covers gas mixtures with equal or higher Helium contents only.

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6.1.4 Low hydrogen approval

.1 Flux-cored or flux-coated wires which have satisfied the requirements for Grades 2, 2Y, 2Y40,3,3Y, 3Y40, 4Y or 4Y40 may, at manufacturer's option, be submitted to the hydrogen test as detailed in4,5. using the manufacturer's recommended welding conditions and adjusting the deposition rate to givea weight of weld deposit per sample similar to that deposited when using manual electrodes.

.2 A suffix H15, H10 or H5 will be added to the grade mark, in the same conditions as for manualarc welding electrodes (see 4.5.3 above) to indicate compliance with the requirements of the test.

6.2 Approval for semi-automatic mulitrun welding

6.2.1 GeneralApproval tests for semi-automatic multirun welding are to be carried out generally in accordance withSection 4, except as required by 6.2, using the semi-automatic mulitrun technique for the preparation ofall test assemblies.

6.2.2 Preparation of deposited metal assemblies

.1 Two deposited metal test assemblies are to be prepared in the downhand position as shown in Fig.4.1, one using the smallest diameter, and the other using the largest diameter of wire intended for thewelding of ship structures. Where only one diameter is manufactured, only one deposited metalassembly is to be prepared.

.2 The weld metal is to be deposited according to the practice recommended by the manufacturer,and the thickness of each layer of weld metal is to be between 2 and 6 mm.

6.2.3 Chemical analysisThe chemical analysis of the deposited weld metal in each test assembly is to be supplied by themanufacturer, and is to include the content of all significant alloying elements.

6.2.4 Mechanical testsOn each assembly, tests are to be made in accordance with 4.2.3, and the results are to comply with therequirements of 4.2.4, appropriate to the required grade.

6.2.5 Preparation of butt weld assemblies

.1 Butt weld assemblies as shown in Fig. 4.2 are to be prepared for each welding position(downhand, horizontal-vertical, vertical upwards, vertical downwards and overhead) for which the wireor wire-gas combination is recommended by the manufacturer.

.2 The downhand assembly is to be welded using, for the first run, wire of the smallest diameter tobe approved and, for the remaining runs, wire of the largest diameter to be approved.

.3 Where approval is requested only in the downhand position, an additional butt weld assembly isto be prepared in that position using wires of different diameter from those required by 6.2.5.2. Whereonly one diameter is manufactured, only one downhand butt weld assembly is to be prepared.

.4 The butt weld assemblies in positions other than downhand, are to be welded using, for the firstrun, wire of the smallest diameter to be approved, and, for the remaining runs, the largest diameter ofwire recommended by the manufacturer for the position concerned.

6.2.6 Radiographic examinationIt is recommended that the welded assemblies are subjected to radiographic examination to ascertain ifthere are any defects in the welds prior to the preparation of test specimens.

6.2.7 On each assembly, tests are to be made in accordance with 4.3.4, and the results are to complywith the requirements of 4.3.5.

6.2.8 Fillet weld testsFillet weld test assemblies are required to be made in accordance with 4.6.1 and 4.6.2, and tested inaccordance with 4.6.3.

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6.3 Approval for automatic multirun welding

6.3.1 GeneralApproval tests for automatic multirun welding are to be carried out generally in accordance with section5 multirun approval, except as required by 5.2, using the automatic multirun technique for thepreparation of all test assemblies.6.3.2 Preparation of deposited metal assemblyOne deposited metal assembly is to be prepared as shown in Fig. 5.1. Welding is to be as detailed in5.2.2.1, except that the thickness of each layer is to be not less than 3 mm.

6.3.3 Chemical analysisThe chemical analysis of the deposited weld metal in this test assembly is to be supplied by themanufacturer, and is to include the content of all significant alloying elements.

6.3.4 Mechanical testsTests on this assembly are to be made in accordance with 5.2.2.3, and the results are to comply with therequirements of 5.2.2.4.

6.3.5 Preparation of butt weld weld assembliesOne butt weld assembly is to be prepared in each welding position which is to be approved. Generally,this will be the downhand position only, in which case only one assembly is required. Preparation of theassembly is to be in accordance with 5.2.3.1.

6.3.6 Radiographic examinationIt is recommended that each assembly be subjected to a radiographic examination to ascertain any defectin the weld prior to testing.

6.3.7 Mechanical testsTests are to be made on each assembly in accordance with 5.2.3.3 and the results are to comply with therequirements of Table 5c. Where more than one assembly is prepared and tested, the number oftransverse tensile and bend test specimens from each assembly may be halved.

6.3.8 Discretionary approvalAt the discretion of each individual Classification Society, wires or wire-gas combinations approved forsemi-automatic multirun welding may also be approved, without additional tests, for automatic multirunwelding approval.This is generally the case when automatic multirun welding is performed in the same conditions ofwelding current and energy as semi automatic welding with the concerned wire-gas combination.

The only difference between the two welding processes in this case is that the welding gun is held by anautomatic device instead of the welder's hand.

6.4 Approval for automatic two-run welding

6.4.1 GeneralApproval tests for automatic two-run welding are to be carried out generally in accordance with therequirements of Section 5.3, except as required by 6.4, using the automatic two-run welding techniquefor the preparation of all test assemblies.

6.4.2 Preparation of butt weld assemblies

.1 Two butt weld test assemblies are to be prepared, generally as detailed in 5.3.1 and 5.3.2, usingplates 12-15 mm and 20-25 mm in thickness. If approval is requested for welding plate thicker than 25mm, one assembly is to be prepared using plates approximately 20 mm in thickness and the other usingplates of the maximum thickness for which approval is requested.

.2 The plate preparation of the test assemblies is to be as shown in Fig. 6.1. Small deviations in theedge preparation may be allowed, if requested by the manufacturer. For assemblies using plates over 25 mm in thickness, the edge preparation is to be reported for information. Deviations or variations willbe expected to form part of the manufacturer's standard recommended procedure for this technique andthickness range.

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.3 The diameters of wires used are to be in accordance with the recommendations of themanufacturer and are to be reported.

6.4.3 Radiographic examinationIt is recommended that the welded assemblies be subjected to radiographic examination to ascertain anydefect in the weld prior to testing, and to confirm full penetration continuously along the major part ofthe welded length of each assembly.

6.4.4 Mechanical testsTests are to be made on each assembly in accordance with 5.3.2.3 to 5.3.2.6 and the results are to complywith the requirements of 5.2.2.4 and Table 5c.

6.4.5 Chemical analysisThe chemical analysis of the deposited weld metal on the second side welded, is to be reported for eachassembly.

6.5 Annual tests and up-grading

6.5.1 Annual tests

.1 Annual tests are to consist of at least:a) Wires approved for semi-automatic or both semi-automatic and automatic multirun welding :

one deposited metal test assembly prepared in accordance with 6.2.2 using a wire of diameter within the range approved for the semi-automatic multirun welding of ship structures.

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60o

12 - 15

6

60o

20 - 25 8

60o

CL


Figure 6.1 Recommended edge preparation for two-run butt weld test assemblies

W17.6 - W17.7

b) Wires approved for automatic multirun welding : one deposited metal test assembly prepared in accordance with 6.3.2 using a wire of diameter within the range approved for automatic multirun welding of ship structures.

c) Wires approved for automatic two-run welding : one butt weld test assembly prepared in accordance with 6.4.2 using plates of 20-25 mm in thickness. The wire diameter used is to be reported.

.2 The test specimens are to be prepared and tested in accordance with the requirements of this Section, except that only the following tests are required:

a) For deposited metal assemblies (semi-automatic and automatic multirun) : one tensile and three impact tests.

b) For butt weld assemblies (automatic two-run) : one transverse tensile, two bend and three impact tests. One longitudinal tensile test is also required where the wire is approved solely for automatic two-run welding.

Note:At the discretion of each individual Classification Society, hydrogen test can be carried out following 4.5.

6.5.2 Up-grading and up-rating

.1 Up-grading of flux cored wires and wire-gas combinations in connection with the impactproperties will be considered as detailed in 4.8.2.2.

.2 Up-rating of flux cored wires and wire-gas combinations with the tensile properties will beconsidered as detailed in 4.8.2.3.

7. Consumables for use in eletroslag and electrogas vertical welding

7.1 General

7.1.1 The requirements for the two-run technique as detailed in Section 5 are applicable for the approvalof special consumables used in electro-slag and electro-gas vertical welding with or without consumablenozzles except as otherwise required by the following requirements especially as regards the number andkind of the test-pieces used for the mechanical tests and taken from the butt welded assemblies.

7.1.2 For Grades 1Y, 2Y, 3Y, 4Y, 2Y40, 3Y40 and 4Y40 approval of the consumables may berestricted for use only with specific types of higher strength steel. This is in respect of the content ofgrain refining elements, and if general approval is required, a niobium treated steel is to be used for theapproval tests.

7.1.3 For these special welding consumables, the prescription 1.2.1 may not be entirely applicable fortechnical reasons.

Where approval is requested for welding of both normal strength and higher strength steel twoassemblies are to be prepared using higher strength steel. Two assemblies prepared using normal strengthsteel may also be required at the discretion of each Classification Society.

7.2 Butt weld tests

7.2.1 Preparation of test assembliesTwo butt weld test assemblies are to be prepared, one of them with plates 20/25 mm thick, the other withplates 35/40 mm thick or more. The grade of the steel to be used for each one of these assemblies mustbe selected according to the requirements given in the figure 5.3 for two-run submerged arc welding.

The chemical composition of the plate, including the content of grain refining elements is to be reported.

The welding conditions and the edge preparation are to be those recommended by the weldingconsumable manufacturer and are to be reported.

7.2.2 Radiographic examinationIt is recommended that the welded assemblies be subjected to a radiographic examination to ascertain ifthere are any defects in the weld prior to the preparation of test specimens.

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7.2.3 Test seriesEach assembly shall be cut to give test specimens according to Figure 7.1.

The length of the assembly should be sufficient to allow the selection of all the test specimens:– 2 longitudinal tensile test specimens with their axis at the centre of the weld.– 2 transverse tensile test specimens.– 2 side bend test specimens.– 2 sets of 3 Charpy-V notch impact test specimens in accordance with Figure 7.1:

.1 set with the notch in the axes of the weld,

.1 set with the notch at 2 mm from the fusion line in the deposited metal.

– 2 macro-sections to the weld (towards the middle of the weld and towards one end).

7.2.4 Results to be obtainedThe results of the tensile, bend and impact tests are to comply with the requirements of paragraph 5.3(two-run welding) for the class of filler product in question.

7.3 Annual tests and up-grading

7.3.1 All factories which manufacture approved consumables for use in electroslag and electrogaswelding must be subject to an annual inspection and tests in accordance with 2.4.

7.3.2 One test assembly must be prepared from plates 20/25 mm thick, and tested as indicated in 7.2.

The following specimens are to be selected:– 1 longitudinal tensile specimen from the axis of the weld,– 1 transverse tensile specimen,– 2 side bend specimens,– 3 Charpy-V specimens notched at the centre of the weld (position 1 Fig. 7.1),– 3 Charpy-V specimens cut out transverse to the weld with their notches at 2 mm from the fusion

line, in the weld,– macro section.

7.3.3 The results to be obtained should meet the requirements given in 5.3 (two-run welding) for theclass of the consumables in question.

7.3.4 Upgrading and uprating

Upgrading and uprating will be considered only at the manufacturers request, at the time of annualtesting. Generally, for this purpose, full tests from butt weld assemblies as indicated in 7.2 will berequired, irrespective of the other tests requested if the concerned consumable is also approved (andpossibly upgraded or uprated) according to Section 5 or Section 6.

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}}

macrography

macrography

1 set of 3Charpy-V test specimen(centre line)

1 set of 3Charpy-V test specimen(2mm from fusion line)

Longitudinal tensile test specimen(centre of weld)

min. 250 min. 250

min. 1500

Transverse tensiletest specimen

Transverse tensiletest specimen

Side bendtest specimen

Side bendtest specimen

Longitudinal tensiletest specimen(centre of weld)

��25 30¥

¥

2

Notch in centre of weld

��

Notch 2 mm from fusion line(weld metal side)

2

2

Figure 7.1 Electroslag and electrogas butt weld test assembly

▲ ▲

Z10.1cont'd

ANNEX IGUIDELINES FOR TECHNICAL ASSESSMENT IN CONJUNCTION WITH PLANNING FOR ENHANCED SURVEYS OF OIL TANERSSPECIAL SURVEY - HULL

Contents:

1. INTRODUCTION2. PURPOSE AND PRINCIPLES

2.1 Purpose2.2 Minimum Requirements2.3 Timing2.4 Aspects to be Considered

3. TECHNICAL ASSESSMENT3.1 General3.2 Methods3.2.1 Design Details3.2.2 Corrosion3.2.3 Locations for Close-up Survey and Thickness Measurement

REFERENCES1. IACS Unified Requirements Z10.1, "Hull Surveys of Oil Tankers."2.TSCF, "Guidance Manual for the Inspection and Condition Assessment of Tanker Structures, 1986."3.TSCF, "Condition Evaluation and Maintenance of Tanker Structures, 1992."

1.0 INTRODUCTIONThese guidelines contain information and suggestions concerning technical assessments which may be ofuse in conjunction with the planning of enhanced special surveys of oil tankers. As indicated in section

5.1.5 of IACS Unified Requirement Z10.1, "Hull Surveys of Oil Tankers," (Ref. 1), the guidelines are arecommended tool which may be invoked at the discretion of an IACS Member Society, whenconsidered necessary and appropriate, in conjunction with the preparation of the required SurveyProgramme.

2.0 PURPOSE AND PRINCIPLES

2.1 PurposeThe purpose of the technical assessments described in these guidelines is to assist in identifying criticalstructural areas, nominating suspect areas and in focusing attention on structural elements or areas ofstructural elements which may be particularly susceptible to, or evidence a history of, wastage ordamage. This information may be useful in nominating locations, areas and tanks for thicknessmeasurement, close-up survey and tank testing.

Critical Structural Areas are locations which have been identified from calculations to require monitoringor from the service history of the subject ship or from similar or sister ships (if available) to be sensitiveto cracking, buckling or corrosion which would impair the structural integrity of the ship.

2.2 Minimum RequirementsHowever, these guidelines may not be used to reduce the requirements pertaining to thicknessmeasurement, close-up survey and tank testing contained in Tables I, II and III, respectively, of Z10.1;which are, in all cases, to be complied with as a minimum.

2.3 TimingAs with other aspects of survey planning, the technical assessments described in these guidelines shouldbe worked out by the Owner or operator in cooperation with the Classification Society well in advance ofthe commencement of the Special Survey, i.e., prior to commencing the survey and normally at least 12to 15 months before the survey's completion due date.

IACS Req. 1994/Rev. 4 1996 v4.0

Z10.1 Annex I

▲

Z10.1I-1

2.4 Aspects to be ConsideredTechnical assessments, which may include quantitative or qualitative evaluation of relative risks ofpossible deterioration, of the following aspects of a particular ship may be used as a basis for thenomination of tanks and areas for survey:

* Design features such as stress levels on various structural elements, design details and extent of use of high tensile steel.

* Former history with respect to corrosion, cracking, buckling, indents and repairs for the particular ship as well as similar vessels, where available.

* Information with respect to types of cargo carried, use of different tanks for cargo/ballast, protection of tanks and condition of coating, if any.

Technical assessments of the relative risks of susceptability to damage or deterioration of variousstructural elements and areas should be judged and decided on the basis of recognised principles andpractices, such as may be found in publications of the Tanker Structure Cooperative Forum (TSCF),(Refs. 2 and 3).

3.0 TECHNICAL ASSESSMENT

3.1 GeneralThere are three basic types of possible failure which may be the subject of technical assessment inconnection with planning of surveys; corrosion, cracks and buckling. Contact damages are not normallycovered by the survey plan since indents are usually noted in memoranda and assumed to be dealt with asa normal routine by Surveyors.Technical assessments performed in conjunction with the survey planning process should, in principle beas shown schematically in Figure 1 depicts, schematically, how technical assessments can be carried outin conjunction with the survey planning process. The approach is based on an evaluation of experienceand knowledge basically related to:

- Design- Corrosion

The design should be considered with respect to structural details which may be susceptible to bucklingor cracking as a result of vibration, high stress levels or fatigue. Corrosion is related to the ageing process, and is closely connected with the quality of corrosionprotection at newbuilding, and subsequent maintenance during the service life. Corrosion may also leadto cracking and/or buckling.

3.2 Methods

3.2.1 Design DetailsDamage experience related to the ship in question and similar ships, where available, is the main sourceof information to be used in the process of planning. In addition, a selection of structural details from thedesign drawings should be included.

Typical damage experience to be considered will consist of:- Number, extent, location and frequency of cracks.- Location of buckles.

This information may be found in the survey reports and/or the Owner's files, including the results of theOwner's own inspections. The defects should be analyzed, noted and marked on sketches.In addition, general experience should be utilized. For example, reference should be made to TSCF's"Guidance Manual for the Inspection and Condition Assessment of Tanker Structures," (Ref. 2), whichcontains a catalogue of typical damages and proposed repair methods for various tanker structural details.Such figures should be used together with a review of the main drawings, in order to compare with theactual structure and search for similar details which may be susceptible to damage. An example is shownin Figure 2.

The review of the main structural drawings, in addition to using the above mentioned figures, shouldinclude checking for typical design details where cracking has been experienced. The factorscontributing to damage should be carefully considered.The use of high tensile steel (HTS) is an important factor. Details showing good service experiencewhere ordinary, mild steel has been used may be more susceptible to damage when HTS, and its higherassociated stresses, are utilized. There is extensive and, in general, good experience, with the use of HTSfor longitudinal material in deck and bottom structures. Experience in other locations, where thedynamic stresses may be higher, is less favorable, e.g. side structures.

Z10.1cont'd

Z10.1 Annex I

IACS Req. 1994, v3.1

▲

Z10.1I-2

In this respect, stress calculations of typical and important components and details, in accordance withthe latest Rules or other relevant methods, may prove useful and should be considered.The selected areas of the structure identified during this process should be recorded and marked on thestructural drawings to be included in the Survey Programme.

3.2.2 CorrosionIn order to evaluate relative corrosion risks, the following information is generally to be considered:

- Usage of Tanks and Spaces- Condition of Coatings- Condition of Anodes- Cleaning Procedures- Previous Corrosion Damage- Ballast use and time for Cargo Tanks- Corrosion Risk Scheme (See Ref. 3, Table 3.1)- Location of Heated Tanks

Ref. 3 gives definitive examples which can be used for judging and describing coating condition, usingtypical pictures of conditions.The evaluation of corrosion risks should be based on information in Ref. 3, together with relevantinformation on the anticipated condition of the ship as derived from the information collected in order toprepare the Survey Programme and the age of the ship.The various tanks and spaces should be listed with the corrosion risks nominated accordingly.

3.2.3 Locations for Close-up Survey and Thickness MeasurementOn the basis of the table of corrosion risks and the evaluation of design experience, the locations forinitial close-up survey and thickness measurement (sections) may be nominated.The sections subject to thickness measurement should normally be nominated in tanks and spaces wherecorrosion risk is judged to be the highest.The nomination of tanks and spaces for close-up survey should, initially, be based on highest corrosionrisk, and should always include ballast tanks. The principle for the selection should be that the extent isincreased by age or where information is insufficient or unreliable.

Z10.1cont'd

Z10.1 Annex I


▲

Z10.1I-3

IACS Req. 1994,v 3.1

Z10.1 Annex I

Z10.1cont'd

Input:Drawings, Reports, Coating ConditionAcceptable Corrosion Collection of Information Anode ConditionAllowance Usage of Tanks

Design Related Risk Corrosion Risk

Acceptance byClass & Owner

Survey

FIGURE 1: TECHNICAL ASSESSMENT AND THE SURVEY PLANNING PROCESS

Analyse:Hull DamageThis Ship

Coating conditionAnodes ConditionUsage of Tanks

Analyse HullDamage forSimilar ShipsWhere Available

Corrosion DamageThis Ship

Hull Damage :General Experience

Corrosion DamageSimilar Ship whereAvailable

Present Areas whereDamage has been foundand Risks consideredhigh. Mark Sketches orDrawings

Location for Thickness Measurement and Close-Up Survey

Survey Programme

▲

Z10.1I-4

Z10.1cont'd

FIGURE 2: TYPICAL DAMAGE AND REPAIR EXAMPLE(REPRODUCED FROM REF. 2)


Z10.1 Annex I

▲

Z10.1I-5

A

LUG

BACKING BRACKET

≥ X

X

VIEW A - A

WEB AND FLAT BAR CROPPED AND PART RENEWED OR ALTERNATIVELY WELDED

A

FULL COLLAR IF FRACTURES IN WEB PLATE ARE SMALL AND ARE REPAIRED BY WELDING

LUG

FACTORS CONTRIBUTING TO DAMAGE

1. Asymmetrical connection of flat bar stiffener resulting in high peak stresses at the heel of the stiffener under fatigue loading.

2. Insufficient area of connection of longitudinal to web plate.

3. Defective weld at return around the plate thickness.

4. High localised corrosion at areas of stress concentration such as flat bar stiffener connections, corners of cut-out for the longitudinal and connection of web to shell at cut-outs.

5 High stress in the web of the transverse.

6. Dynamic sea way load/ship motions.

TYPICAL DAMAGE PROPOSED REPAIR

FIGURE 1

FIGURE 1

TANKER STRUCTURE CO-OPERATIVE FORUM

SUBJECT: CATALOGUE OF STRUCTURAL DETAILS

SHELL PLATING OR LONGITUDINAL BULKHEAD

★FRACTURE

FLAT BAR STIFFENER

FRACTURED WELD/WEB ★

FRACTURE

SIDE SHELL OR BULKHEAD LONGITUDINAL

★FRACTURE

WEB PLATING

VIEW A - A

NOTE ★ONE OR MORE FRACTURES MAY OCCUR

A A

WEB FLAT BAR STIFFENER

LOCATION: Connection of longitudinals to transverse webs

EXAMPLE No. 1 : Web and flat bar fractures at cut-outs for longitudinal stiffener connections

ANNEX IGUIDELINES FOR TECHNICAL ASSESSMENT IN CONJUNCTION WITHPLANNING FOR ENHANCED SURVEYS OF BULK CARRIERSSPECIAL SURVEY - HULL

Contents:

1. INTRODUCTION2. PURPOSE AND PRINCIPLES

2.1 Purpose2.2 Minimum Requirements2.3 Timing2.4 Aspects to be Considered

3. TECHNICAL ASSESSMENT3.1 General3.2 Methods3.2.1 Design Details3.2.2 Corrosion3.2.3 Locations for Close-up Survey and Thickness Measurement

REFERENCES1. IACS Unified Requirements Z10.2, "Hull Surveys of Bulk Carriers."2.TSCF, "Guidance Manual for the Inspection and Condition Assessment of Tanker Structures, 1986."3.TSCF, "Condition Evaluation and Maintenance of Tanker Structures, 1992."4. IACS, "Bulk Carriers: Guidelines for Surveys, Assessment and Repair of Hull Structures, 1994."

1.0 INTRODUCTIONThese guidelines contain information and suggestions concerning technical assessments which may be ofuse in conjunction with the planning of enhanced special surveys of bulk carriers. As indicated in section5.1.5 of IACS Unified Requirement Z10.2, "Hull Surveys of Bulk Carriers," (Ref. 1), the guidelines are arecommended tool which may be invoked at the discretion of an IACS Member Society, whenconsidered necessary and appropriate, in conjunction with the preparation of the required SurveyProgramme.

2.0 PURPOSE AND PRINCIPLES

2.1 PurposeThe purpose of the technical assessments described in these guidelines is to assist in identifying criticalstructural areas, nominating suspect areas and in focusing attention on structural elements or areas ofstructural elements which may be particularly susceptible to, or evidence a history of, wastage ordamage. This information may be useful in nominating locations, areas, holds and tanks for thicknessmeasurement, close-up survey and tank testing.

Critical Structural Areas are locations which have been identified from calculations to require monitoringor from the service of the subject ship or from similar or sister ships (if available) to be sensitive tocracking, buckling or corrosion which would impair the structural integrity of the ship.

2.2 Minimum RequirementsHowever, these guidelines may not be used to reduce the requirements pertaining to thicknessmeasurement, close-up survey and tank testing contained in Tables I, II and paragraph 2.5, respectively,of Z10.2; which are, in all cases, to be complied with as a minimum.

2.3 TimingAs with other aspects of survey planning, the technical assessments described in these guidelines shouldbe worked out by the Owner or operator in cooperation with the Classification Society well in advance ofthe commencement of the Special Survey, i.e., prior to commencing the survey and normally at least 12to 15 months before the survey's completion due date.

IACS Req. 1992/Rev. 4 1996 v5.2

Z10.2 Annex I

Z10.2cont'd

▲

▲

Page I-1

2.4 Aspects to be Considered

Technical assessments, which may include quantitative or qualitative evaluation of relative risks ofpossible deterioration, of the following aspects of a particular ship may be used as a basis for thenomination of holds, tanks and areas for survey:

*Design features such as stress levels on various structural elements, design details and extent of use of high tensile steel.*Former history with respect to corrosion, cracking, buckling, indents and repairs for the particular ship as well as similar vessels, where available.*Information with respect to types of cargo carried, protection of tanks, and condition of coating, if any, of holds and tanks.

Technical assessments of the relative risks of susceptibility to damage or deterioration of variousstructural elements and areas should be judged and decided on the basis of recognized principles andpractices, such as may be found in the IACS publication "Bulk Carriers: Guidelines for Surveys,Assessment and Repair of Hull Structure," (Ref. 4).

3.0 TECHNICAL ASSESSMENT

3.1 General

There are three basic types of possible failure which may be the subject of technical assessment inconnection with planning of surveys; corrosion, cracks and buckling. Contact damages are not normallycovered by the survey plan since indents are usually noted in memoranda and assumed to be dealt with asa normal routine by Surveyors.

Technical assessments performed in conjunction with the survey planning process should, in principle beas shown schematically in Figure 1 depicts, schematically, how technical assessments can be carried outin conjunction with the survey planning process. The approach is based on an evaluation of experienceand knowledge basically related to:

- Design- Corrosion

The design should be considered with respect to structural details which may be susceptible to bucklingor cracking as a result of vibration, high stress levels or fatigue. Corrosion is related to the ageing process, and is closely connected with the quality of corrosionprotection at newbuilding, and subsequent maintenance during the service life. Corrosion may also leadto cracking and/or buckling.

3.2 Methods

3.2.1 Design Details

Damage experience related to the ship in question and similar ships, where available, is the main sourceof information to be used in the process of planning. In addition, a selection of structural details from thedesign drawings should be included.

Typical damage experience to be considered will consist of:- Number, extent, location and frequency of cracks.- Location of buckles.

This information may be found in the survey reports and/or the Owner's files, including the results of theOwner's own inspections. The defects should be analyzed, noted and marked on sketches.

In addition, general experience should be utilized. For example, Figure 2 shows typical locations in bulkcarriers which experience has shown may be susceptible to structrual damage. Also, reference should bemade to IACS's "Bulk Carriers: Guidelines for Survey, Assessment and Repair," (Ref. 4) which containsa catalogue of typical damages and proposed repair methods for various bulk carrier structural details.

Z10.2cont'd


Z10.2 Annex I

▲

Page I-2

Such figures should be used together with a review of the main drawings, in order to compare with theactual structure and search for similar details which may be susceptible to damage. An example is shownin Figure 3.

The review of the main structural drawings, in addition to using the above mentioned figures, shouldinclude checking for typical design details where cracking has been experienced. The factorscontributing to damage should be carefully considered.

The use of high tensile steel (HTS) is an important factor. Details showing good service experiencewhere ordinary, mild steel has been used may be more susceptible to damage when HTS, and its higherassociated stresses are utilized. There is extensive and, in general, good experience, with the use of HTSfor longitudinal material in deck and bottom structures. Experience in other locations, where thedynamic stresses may be higher, is less favorable, e.g. side structures.

In this respect, stress calculations of typical and important components and details, in accordance withthe latest Rules or other relevant methods, may prove useful and should be considered.

The selected areas of the structure identified during this process should be recorded and marked on thestructural drawings to be included in the Survey Programme.

3.2.2 Corrosion

In order to evaluate relative corrosion risks, the following information is generally to be considered:- Usage of Tanks, Holds and Spaces- Condition of Coatings- Condition of Anodes- Cleaning Procedures- Previous Corrosion Damage- Ballast use and time for Cargo Holds- Risk of Corrosion in Cargo Holds and Ballast Tanks- Location of Ballast Tanks Adjacent to Heated Fuel Oil Tanks

Ref. 3 gives definitive examples which can be used for judging and describing coating condition, usingtypical pictures of conditions.For bulk carriers, Ref. 4 should be used as the basis for the evaluation, together with relevant informationon the anticipated condition of the ship as derived from the information collected in order to prepare theSurvey Programme and the age of the ship.

The various tanks, holds and spaces should be listed with the corrosion risks nominated accordingly.

3.2.3 Locations for Close-up Survey and Thickness Measurement

On the basis of the table of corrosion risks and the evaluation of design experience, the locations forinitial close-up survey and thickness measurement (sections) may be nominated.

The sections subject to thickness measurement should normally be nominated in tanks, holds and spaceswhere corrosion risk is judged to be the highest.

The nomination of tanks, holds and spaces for close-up survey should, initially, be based on highestcorrosion risk, and should always include ballast tanks. The principle for the selection should be that theextent is increased by age or where information is insufficient or unreliable.

Z10.2 Annex I

Z10.2cont'd


▲

Page I-3

Input:Drawings, Reports, Coating ConditionAcceptable Corrosion Collection of Information Anode ConditionAllowance Usage of Tanks

Design Related Risk Corrosion Risk

Acceptance byClass &Owner

Survey

Figure 1: Technical Assessment & the Survey Planning Process

Z10.2cont'd


Z10.2 Annex I

▲

Analyse:Hull DamageThis Ship

Analyse HullDamage forSimilar ShipsWhere Available

Coating conditionAnodes ConditionUsage of Tanks

Corrosion DamageThis Ship

Corrosion DamageSimilar Ship whereAvailable

Present Areas whereDamage has been foundand Risks consideredhigh. Mark Sketches orDrawings

Hull Damage :General Experience

Location for Thickness Measurement and Close-Up Survey

Survey Programme

Page I-4

FIGURE 2: TYPICAL LOCATIONS SUSCEPTIBLE TO STRUCTURAL DAMAGE OR CORROSION

Z10.2cont'd


Z10.2 Annex I

▲

Page I-5

FIGURE 3: TYPICAL DAMAGE AND REPAIR EXAMPLE(REPRODUCED FROM REF: 4)

Z10.2cont'd

Z10.2 Annex I


Page I-6

��

3276/23

AREA 1

Detail of damage

Sketch of damage Sketch of repair

3276/04

Side shell frames and end brackets (separate bracket configuration)

Fractures in brackets at termination of frame

Separate Bracket Configuration

Side shell

Hopper tank

x

0,3Y

Y

S

S

S

S

Modified brackets

Notes on possible cause of damage

0,3x

Y

Topside tankTopside tank

FracturesSide shell

Hopper tank

Structural item

X

S = Sniped end

Snipe frame��

Snipe frame�

EXAMPLE 1

Notes on repairs

1. This type of damage is due to stress concentration. 1. For small fractures e.g. hairline fractures, the fracture can be 'veed' out, welded up, ground and examined by NDT for fractures.

2. For larger/significant fractures consideration is to be given to cropping and partly renewing/renewing the frame brackets. If renewing the brackets, ends of frames can be sniped to soften them.

3. If felt prudent, soft toes are to be incorporated at the boundaries of the bracket to the wing tanks.

4. Attention to be given to the structure in wing tanks in way of the extended bracket arm i.e. reinforcement provided in line with the bracket arm.

Z10.2 Annex II - Sheet 14

Z10.2Annex cont'd


Page II-23

Upper stoolTopside tank

HoppersidetankDouble bottom tank

Lower stool

E

B

A

B

D

Hatchopening

Hatchopening

Hatchopening

E

CArea

EArea

A cargo hold, transverse bulkhead

Typical areas of deck plating inside lineof hatch openings between cargo hold hatches

Typical transverse section

AAreas , andB D

Thickness to be reported on TM5-BC

Thickness to be reportedd on TM3-BC, TM4-BC,TM6-BC and TM7-BC as appropriate

Close-up Survey and Thickness Measurement Areas

C

Thickness to be reported on TM6-BC

Z13

Voyage Repairs and Maintenance

Where repairs to hull, machinery or equipment, which affect or may affect classification, are to becarried out by a riding crew during a voyage they are to be planned in advance. A complete repairprocedure including the extent of proposed repair and the need for surveyor’s attendance during thevoyage is to be submitted to and agreed upon by the Surveyor reasonably in advance. Failure to notifythe Classification Society, in advance of the repairs, may result in suspension of the vessel’s class.

The above is not intended to include maintenance and overhaul to hull, machinery and equipment inaccordance with manufacturer’s recommended procedures and established marine practice and whichdoes not require the Classification Society’s approval; however, any repair as a result of suchmaintenance and overhauls which affects or may affect classification is to be noted in the ship’s log andsubmitted to the attending Surveyor for use in determining further survey requirements.

Note: Annexed “Guidelines for the Survey of Voyage Repairs” is a recommendation and is not a mandatory requirement under this UR Z13.

Z131995(Rev 11995)

IACS Req. 1995/Rev 1 1995

▲

▲

ANNEX

GUIDELINES FOR THE SURVEYOF VOYAGE REPAIRS

The purpose of these notes is to provide guidance to the field Surveyors in dealing with voyage hullrepairs and is to be considered in addition to the Rules of the Classification Society; no part of this guideis intended to conflict with Rules of the Classification Society.

A. A meeting is to be held with the owners prior to commencement of hull repairs during a vessel’svoyage to discuss and confirm the following :

1. It is the owner’s responsibility to ensure continued effectiveness of the structure, includingthe longitudinal strength and the watertight/weathertight integrity of the vessel.

2. Extent of intended repairs. All repairs to be based on the Classification Society’srecommendations and/or concurrence.

3. Availability of pertinent drawings.

4. Verification of new materials regarding certification, grade and scantlings. Verified millsheets to remain on board and to be provided to attending Surveyor examining completedrepairs.

5. Verification of welding consumables regarding certification and suitability for materialsinvolved. Check on availability of drying ovens, holding containers, etc.

6. Verification of the qualification of welders and supervisory personnel, qualificationrecords to remain on board and to be provided to attending Surveyor examining completedrepairs.

7. Review of intended repair.

8. Review of the intended provisions to facilitate sound weldments, i.e. cleaning, preheating(if applicable) adherence to welding sequence principles.

Further, it might be necessary to restrict welding to certain positions and prohibit weldingin more difficult positions when the ship’s motions might influence the quality of thewelding.

9. Review of intended working conditions, i.e. staging, lighting, ventilation, etc.

10. Review of intended supervision and quality control.

11. Completed repairs are to be examined and tested as required to the satisfaction of theattending Surveyor.

Note: All details and results of subject meeting to be covered by a memorandum. A copy of thismemorandum is to be placed on board and to be provided to the attending Surveyorexamining repairs. In addition, a copy is to be sent/faxed to the arrival port wherecompleted repairs will be examined.

Z13 Annex

Z13cont'd

IACS Req. 1995

▲

Z13 Annex - 1

Z13 Annex

B. Any contemplated repairs to primary hull structures, i.e. main longitudinal and transversemembers and their attachments, are to be submitted to the Classification Society for review priorto commencing voyage repairs.

Any repairs to primary hull structures shall require attendance by a Surveyor riding-ship survey orat regular intervals to confirm fit-up, alignment, general workmanship and compliance withrecommendations.

NDT of completed repairs to primary structure to be carried out to attending Surveyor’s satisfaction.

Repairs to other hull structural parts may be accepted based on examination upon completion of repairs.

C. No hull repairs carried out by a riding crew should be accepted unless:

1. The initial meeting had been carried out and conditions found satisfactory.

2. A final satisfactory examination upon completion was carried out.

Z13cont'd

No. 12

Guidelines for Surface Finish of Hot RolledSteel Plates and Wide Flats

1. Scope

These guidelines give some criteria recommended for the surface finish for hull structural steelplates and wide flats in accordance with requirement W11 as well as the treatment ofimperfections and defects which may occasionally occur on the surfaces of these products.They do not cover quality requirements for the edges.

At the individual Classification Society's discretion these guidelines may also be applied toother steel grades.

Note

The criteria contained herein have been based on the consideration that surface imperfections and defectson hull steels may impair the proper coating of tanks and hulls and this may reduce the corrosionresistance.

Moreover, they may increase the frictional resistance of the hull and thereby impair the economy of theservice. Surface defects may also adversely affect the strength of the structure. Special provisions withrespect to the surface finish are therefore deemed necessary.

2. Manufacturer's Responsibility

The responsibility for the required surface finish rests with the manufacturer of the material,who is to take the necessary precautions and to inspect the products prior to delivery. At thatstage, however, rolling or heat treatment scale may conceal surface discontinuities. If, duringthe subsequent descaling or working operations, the material is found to be defective, theSurveyor may require materials to be repaired or rejected.

3. Acceptance Criteria

3.1 General Surface Finish

All products must have a workmanlike finish and must be free from defects and imperfectionswhich may impair their proper workability and use. This may, however, include somediscontinuities of a harmless nature, minor imperfections, e.g. pittings, rolled-in scale,indentations, roll marks, scratches and grooves which cannot be avoided completely despiteproper manufacturing and which will not be objected to provided they do not exceed theacceptable limits contained herein.

3.2 Imperfections

IACS Rec. 1983

▼

No. 12(1983)

Notwithstanding this, the products may have imperfections exceeding the discontinuities inherent to themanufacturing process, as defined under item 3.1. In such cases, limits for their acceptability are to beagreed with the Classification Society, taking the end use of the product into consideration.

3.3 Defects

Cracks, shells, sand patches and sharp edged seams are always considered defects which would impairthe end use of the product and which require rejection or repair, irrespective of their size and number.The same applies to other imperfections exceeding the acceptable limits.

4. Repair Procedures

4.1 Grinding

4.1.1 Grinding may be applied provided:

(a) the nominal product thickness will not be reduced by more than 7% or 3 mm, whichever is the less

(b) each single ground area does not exceed 0,25 m2 and

(c) all ground areas do not exceed 2% of the total surface in question.

Ground areas lying in a distance less than their average breadth to each other are to be regarded as onesingle area.

4.1.2 Ground areas lying opposite each other on both surfaces must not decrease the product thicknessby values exceeding the limits as stated under 4.1.1.

4.1.3 The defects or unacceptable imperfections are to be completely removed by grinding.

The ground areas must have smooth transitions to the surrounding surface of the product. Completeelimination of the defects may be verified by a magnetic particle or dye penetrant test procedure at theSurveyor's discretion.

4.1.4 Where necessary, the entire surface may be ground to a depth as given by the under thicknesstolerances of the product.

4.2 Welding Repair

Local defects which cannot be repaired by grinding as stated under 4.1 may be repaired with theSurveyor's consent by chipping and/or grinding followed by welding subject to the following conditions:

4.2.1 Any single welded area shall not exceed 0,125 m2 and the sum of all areas shall not exceed 2%of the surface side in question.

The distance between two welded areas shall not be less than their average width.

4.2.2 The weld preparation must not reduce the thickness of the product below 80% of the nominalthickness. For occasional defects with depths exceeding the 80% limit, special consideration at theSurveyor's discretion will be necessary.

4.2.3 The repair shall be carried out by qualified welders using an approved procedure for theappropriate steel grade. The electrodes shall be of low hydrogen type and must be dried in accordancewith the manufacturer's requirements and protected against rehumidification before and during welding.

▼

No. 12

No. 12cont'd

IACS Rec. 1984

4.2.4 All weldings are to be of reasonable length and must have at least 3 parallel welding beads. Thedeposited metal must be sound without any lack of fusion, undercut, cracks and other defects whichcould impair the workability or use of the product.Welding is to be performed with one layer of beads in excess, which is subsequently to be groundsmooth to the surface level.

4.2.5 Products which are to be supplied in a heat treated condition are to be welded prior to the heattreatment; otherwise, a new heat treatment may be required.

Products supplied in the controlled rolled or as rolled condition may require a suitable heat treatmentafter welding. However, the post weld heat treatment may be omitted provided the manufacturer hasdemonstrated by a procedure test that the required properties will be maintained without heat treatment.

4.2.6 The finished products are to be presented to the Surveyor for acceptance. The soundness of therepair may be verified by ultrasonic, magnetic particle or dye penetrant methods at the Surveyor'sdiscretion.

4.2.7 For every welding repair the manufacturer must provide the Surveyor with a written report and asketch showing sizes and location of the defects and full details of the repair procedure including thewelding consumables, post weld heat treatment and non-destructive testing.

IACS Rec. 1986

No. 12

No. 12cont'd

▼ ▼

Guide for inspection of ship hull welds1. Scope

The purpose of this document is to give guidelines for quality control of ship hull welds duringnewbuilding. The document contains general guidance for the application of non-destructiveexamination (NDE) methods, extent of examinations and recommended quality level forsatisfactory workmanship.The guidelines contained herein are intended for welds in structural members where materialsclass III and IV are used according to UR S6, that is the bulk of the welds within 0,4Lamidships.As a general principle, regardless of the application of the recommendations in this documentby the individual Society, a plan of the areas to be examined and the methods to be employed,should be submitted for approval.

2. Basic Conditions

The guide is based on the conditions mentioned below.

2.1 Type of material

Normal and high strength structural steels according to UR W11.Hull forgings according to UR W7.Hull castings according to UR W8.

2.2 Welding processes

Gas metal arc, gas tungsten arc, flux cored arc, shielded metal arc, submerged arc, electroslagand electrogas welding.Consumables according to UR W17.

2.3 Weld joint types

Butt weld joints, T, corner and cruciform joints with and without full penetration, fillet weldjoints.

2.4 Types of discontinuities

The main types of discontinuities mentioned in this document are listed below. Reference isgiven to ISO 6520-1982 (E/F) which use the IIW/IIS classification numbers given in brackets.Porosity (200), slag inclusions (300), undercut (5011, 5012), underfill (509, 511, 606),excessive weld reinforcement (502-504), overlap (506), cracks (101-106), lack of fusion (401),incomplete penetration (402), lamellar tears.

2.5 Examination methods

For detection of surface discontinuities Visual examination (VE)

Magnetic particle examination (ME)Liquid penetrant examination (PE)

For detection ofembedded discontinuities Ultrasonic examination (UE)

Radiographic examination (RE)

3. Structural Elements and Weldments

Reference is given to UR S6 for the definition of hull structural elements and material classes Ito V.

▼

No. 20

No. 20(1988)

IACS Rec. 1988

This document is intended for weldments in structural elements where materials class III andIV are used, that is the bulk of the welds within 0,4L amidships.Welds in structural members requiring material classes I or II may be subject to less stringentrequirements. For welds in material class V in specially high stressed areas more stringentrequirements should be applied. It is left to each Society to define the specific requirements.

Relaxation of requirements for low stressed welds within the scope of the document is left tothe discretion of each Society.

4. Definition of Weld Joint Configuration Groups with Respect to Suitable NDE-Methods

4.1 GeneralThe different types of weldments are divided into four groups of weld joint configurations withrespect to the applicability of methods for detection of embedded discontinuities (UE and RE)as defined in 4.2 - 4.5. Types of weldments normally belonging to the four groups are givenfor guidance, see also Table 1.

4.2 Weld joint configuration group AWeldments for which both UE and RE are applicable.Normally this group includes butt weld joints (of full penetration) in plates of minimum 10 mmplate thickness.

4.3 Weld joint configuration group BWeldments for which only RE is applicable.Normally this group includes butt welded joints in plates of thickness less than 10 mm (orpartly penetrated butt welds).

4.4 Weld joint configuration group CWeldments for which only UE is applicable.Normally this group includes T-joints, corner-joints and cruciform joints of full penetration inplates of minimum 10 mm thickness.

4.5 Weld joint configuration group DWeldments for which neither UE nor RE is applicable.Normally this group includes T, corner and cruciform joints of partly penetration or platethickness less than 10 mm and fillet welded joints.

4.6 Types of weld discontinuities, capability for detectionThe general capability of different test methods to detect weld discontinuities are shown inTable 1 for each group of weld joint configurations.

5. Qualification of Personnel

The shipbuilder is responsible for supplying properly trained operators certificated inaccordance with an acceptable international or national scheme. Records of operators and theircurrent certificates are to be kept and made available to the surveyors for inspection.

6. Examination Techniques

6.1 General

6.1.1 ProcedureIn general a NDE-procedure specification should be worked out for each specific NDE-method, see 6.2.2, 6.3.2, 6.4.2, 6.5.2 and 6.6.2. In addition the procedure specification shouldcontain these general items:Surface requirements, cleaning and preparationLocation reference identification and markingEvaluating of findings and indicationsReporting

▼

No. 20

No. 20cont'd

IACS Rec. 1988

No

. 20

▼

No. 20

cont'd

IAC

S R

ec. 1988

▼

TABLE 1 CAPABILITY OF DETECTION OF DISCONTINUITIES1) 2)

WELD JOINT METHODS FOR DETECTION OF SUBFACE METHODS FOR DETECTION OF EMBEDDEDCONFIGURATION DISCONTINUITIES3) DISCONTINUITIES

VE ME/PE UE4) RE

Group A Porosity Undercut Porosity PorosityUndercut Overlap Slag inclusions Slag inclusionsUnderfill Cracks Cracks Undercut(Overflap) Lack of fusion Lack of fusion Underfill

Butt welds of plate (Cracks) Incomplete penetration Incomplete penetration (Cracks)thickness ≥ 10 mm (Lack of fusion) Porosity Lammellar tears (Lack of fusion)

Incomplete penetration Incomplete penetration

Group B Porosity Undercut PorosityUndercut Overlap Slag inclusionsUnderfill Cracks Undercut(Overflap) Lack of fusion Not Applicable Underfill

Butt welds of plate (Cracks) Incomplete penetration (Cracks)thickness < 10 mm (Lack of fusion) Porosity (Lack of fusion)

Incomplete penetration Incomplete penetration

Group C Porosity Undercut PorosityT-joints, corner- Undercut Overlap Slag inclusionsjoints and cruciform Underfill Cracks Cracksjoints of plate (Overlap) Porosity Lack of fusion Not Applicablethickness ≥ 10 mm (Cracks) Incomplete penetrationand full penetration Lamellar tears

Group D Porosity UndercutT-joints, corner and Undercut Overlapcruciform joints of Underfill Cracksplate thickness < 10 mm (Overlap) Porosity Not Applicable Not Applicableor partly penetration. (Crack)Fillet welds

NOTES: 1) The table is given for general information. Not all decisive factors are included.2) For discontinuities in brackets the capability is marginal.3) The discontinuities listed for VE and PE are open surface, discontinuities only. ME may also detect discontinuities just below the surface.

This procedure should in addition cover items specific to the NDE technique in question.These items are, depending on NDE technique listed below.

6.1.2 SensitivityEach applied NDE technique should meet with certain requirements in order to assureexamination at a required sensitivity level.Direct or indirect sensitivity requirements for the individual NDE techniques are given below.

6.1.3 Reference Documents

The examination should, in order to assure examination quality and fulfil sensitivityrequirements, be performed according to nationally or internationally recognised NDEstandards, recommendations or other documents accepted by the Society. Such referencedocuments should meet the minimum requirements given by this Guide.The reference documents may be replaced by equivalent or similar documents issued by theSociety.

6.2 Visual Examination

6.2.1 General

The technique makes use of visual observation to reveal weld surface discontinuities andirregularities like undercut, surface porosity and excess weld reinforcement. If necessarymechanical aids (gauges and rulers) should be used to assess and size discontinuities.

6.2.2 Procedure

Items to be covered by the procedure are:Viewing conditionsAids to enhance visibilityRulers and gauges to be used

6.2.3 Sensitivity requirements

Direct visual examination requires an illumination at the point of observation which makes itpossible to reveal and describe unacceptable surface discontinuities. The welds should bepresented clean and without paint.Reporting should consist of acceptance or not for each weld section and, if relevant orotherwise, give the type and size of the discontinuity causing non-acceptance.

6.3 Magnetic particle examination

6.3.1 General

The technique to be used is detection of magnetic leakage fluxes from surface discontinuities,and to a certain extent also subsurface discontinuities, in ferromagnetic materials by means offerromagnetic particles during application of a magnetic field.

6.3.2 Procedure

Items to be covered by the procedure are:Magnetising procedure and equipmentDetection mediaField strength measurement/verificationDetection media application Viewing conditionsDemagnetizationPrecautions against arcing

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The examination should provide search for weld surface discontinuities of any orientation.The surface to be examined may be as welded, but should be clean and dry and, if noticeableirregularities exist, smoothed by grinding.The peak value of the tangential magnetic field strength in the area being examined should bebetween 2.4 and 4.0 kA/m.Magnetisation by AC or HWDC should be used.Fluorescent or non-fluorescent magnetic inks may be applied.The preparation and illumination (by visible or ultraviolet light, depending on type of detectionmedia) of the surface under examination should be sufficient to reveal and describe anyunacceptable surface discontinuity.

6.4 Penetrant examination

6.4.1 General

The technique applies a low surface tension liquid, which penetrates into surface opendiscontinuities. By use of a suitable developer the penetrated liquid can be made visible andthus a discontinuity indicated.

6.4.2 Procedure

Items to be covered by the procedure are:Reference/calibration/verification specimensSurface cleaning and preparationObject temperaturePenetrant and developer typePenetrant application and removalPenetration timeDeveloper applicationDevelopment time.


The surface to be examined may be as welded, but should be clean and dry and withoutnoticeable irregularities. In order to avoid masking of discontinuities, grinding should beapplied with considerable care.Fluorescent or visible, water washable, solvent removable or post emulsified penetrants may beapplied. Developers may be aqueous, non-aqueous wet or dry powders.Outside the temperature range 5 - 50°C reference comparator blocks should be used.Penetration times should typically be between 20 and 60 minutes and development timesminimum 15 minutes. When the temperature is below 15°C the development times should beminimum 30 minutes. During the first 2 minutes of development the building up of indicationsshould be carefully watched. The illumination (by visible or ultraviolet light, depending on type of detection media) of thesurface under examination should be sufficient to reveal and describe any unacceptable surfacediscontinuity.

6.5 Ultrasonic examination

6.5.1 General

The technique to be used is the ultrasonic pulse echo technique supplying normal and angleprobes. The examination may be performed manually or by mechanised or automatedequipment.

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6.5.2 Procedure

Items to be covered by the procedure are:Equipment typeProbe types, frequencies and anglesCalibration block(s)Reference block(s)CouplantEquipment calibration and checks (linearity, resolution, wear)Sensitivity setting and transfer correctionsExamination of parent materialScanning techniquesSizing techniques


The weld examination should cover search for longitudinal and transverse weld discontinuitiesusing at least one angle probe from each side of the weld. The weld geometry may require alsonormal probes to be used to reveal weld discontinuities.The weld examination should be done using the echo from a 3 mm diameter side drilled hole asreference (defining the Reference Level).Other reflectors such as flat bottomed holes or notches may replace the side drilled hole asreference reflector, provided the same sensitivity is achieved, for example the DGS- method(Distance Gain Sensitivity - m).

6.6 Radiographic examination

6.6.1 General

The technique that should be used is projective imaging using X or Gamma-rays with film asthe recording and displaying medium. For material thickness less than 15 mm X-rays are to bepreferred. Other displaying media, e.g. fluoroscopic screens, may be applied provided thebasic requirements to the applied technique are met.

6.6.2 Procedure

Items to be covered by the procedure are:Radiation source, type and focal spot sizeGeometry of radiographic setupFilm typeIntensifying screensFilm coverageImage quality indicatorsFilm identification markingExposure conditionsFilm processingFilm densityFilm viewing conditions


The following wire image quality indicator sensitivities, or equivalent for other types of imagequality indicators (IQI), should be achieved:

Plate thickness IQI Wire Sensitivity≤ 10 mm 2,0%

80 mm 1,0%> 80 mm 0,8 mm/t

t is the plate thickness. For thickness between 10 and 80 mm the required sensitivity is foundby linear interpolation between the above values.

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7. Extent of Examination

The extent of examination is defined as the percentage of the length of weldments which is tobe examined by a specific method.The extent of examination will depend on the type of ship and the location of the joints. Typical figures are given in Table 2 below.

Table 2 Extent of Examination

For group A either RE or UE, or a combination of the two methods may be chosen.The welds should be examined in sections of length in the range 0,2 to 0,5 m for RE and about1m for UE.The sections to be examined should be selected by the Surveyor. These sections shouldprincipally be evenly distributed, and special attention should be paid to weld crossings anderection welds.The extent of examination may be modified at the discretion of the Surveyor depending on theoverall quality of the production welds, the welding procedures used and the quality controlprocedures employed at the shipyard.

8. Quality level

The recommended quality level expressed through recommended acceptance criteria, isspecified for each test method in Tables 3, 4 and 5. When ultrasonic examination is applied,reference curves of the type shown in Fig 1 should be used.Acceptance criteria of other codes or standards may be in agreement with the Society fully orpartly replace Tables 3 through 5.Discontinuities which are not found acceptable according to Table 3 through 5 or eventuallyother criteria agreed upon, are here referred to as "non-conforming" discontinuities.

9. Non-conforming weldments

9.1 Extended examination

If a non-conforming discontinuity is detected by a method which is applied to an extent lessthan 100%, the lengths welded immediately before and after the section containing thediscontinuity should be examined by this method. If systematically repeated discontinuities arerevealed the extent of examination may be increased at the Surveyors discretion for weldsmanufactured under same conditions and where similar defects may be expected.

9.2 Corrective actions

If non-conforming discontinuities are found to occur regularly, the Surveyor may require thatthe welding procedures are reassessed before continuation of the welding and necessary actionsshould be taken to bring the production to the required quality level.

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Weld joint

Configuration groups VE ME/PE1) UE RE

A 100% Spot2) 2–4% 2–4%B 100% Spot2) – 2–4%C 100% Spot2) 2–4% –D 100% Spot2) – –

1) To be used as an adjunct to VE and especially at critical points for example at crossings, fillet weld ends, excavations and repairs.

2) To be judged by the Surveyor.

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9.3 Repair and testing

Detected non-conforming discontinuities are to be repaired unless they are found acceptable bythe Society.Removal of weld discontinuities and repair are to be performed in accordance with a procedureapproved by the Society.Parts of weldments which are repaired should be examined by VE and one other surfaceinspection method (ME or PE) as well as one volumetric inspection method (UE or RE).

Table 3 Recommended Acceptance Criteria For VE, ME and PE.

NOTE:1) Discontinuities on a line where the distance between the discontinuities is shorter than thelongest discontinuity are to be regarded as one continuous discontinuity.

2) t: Plate thickness of the thinnest plate in the weld connection.3) b: Width of weld reinforcement.

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TYPE OF SURFACE RECOMMENDED ACCEPTANCE CRITERIADISCONTINUITY FOR VE, ME AND PE

POROSITYMax. pore diameter, d: 3,0 mmMin. distance to adjacent pore: 2,5d

UNDERCUTMax. depth: 0,5 mm

UNDERFILL1)2)

Max. depth 1,5 mmMax. length t/2

EXCESSIVE WELDREINFORCEMENT3)

Max. height b/5, max. 6 mm

OVERLAP1)2)

Max. length: t

CRACKS Not accepted

LACK OF FUSIONMax. length: Not accepted

INCOMPLETE PENETRATION1)2)

Max. height: t/10, max. 1,5 mmMax. length: t

Table 4 Recommended Acceptance Criteria for RE

NOTE:1) Discontinuities on a line where the distance between the discontinuities is shorter than thelongest discontinuity are to be regarded as one continuous discontinuity.

2) t: Plate thickness of the thinnest plate in the weld connection.3) If the distance between parallel slag inclusions, measured in the transverse direction of welding

is less than 3 times the width of the largest slag inclusion, the slag inclusions are regarded asone discontinuity.

4) Excavation and repair probably not necessary for lengths up to t.

Table 5 Recommended Acceptance Criteria for UE

1) t: Plate thickness of the thinnest plate in the weld connection.2) The length of an indication is to be measured as the length where the echo height is

above the specified value. Indications from one or more discontinuities on a line where the distance between the indications is less than the length of the longest indication are to be regarded as one continuous indication.

3) Excavation and repair probably not necessary for lengths up to t.

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TYPE OF DISCONTINUITY ACCEPTANCE CRITERIA FOR RE

POROSITY, ISOLATED2)

Max. pore diameter, d: t/4, max. 3 mmMin. distance to adjacent pore: 2,5d

POROSITY, CLUSTEREDMax. pore diameter, d:1) 3 mmMax. length of cluster:1) 25 mm

SLAG INCLUSION1)2)3)4)

Max. width: 3,0 mmMax. length: t or max 25 mm

UNDERCUT See table 3

UNDERFILL See table 3

CRACKS Not accepted

LACK OF FUSION Not accepted

INCOMPLETE PENETRATION1)2)4)

Max. length t or max 25 mm

ACCEPTANCE CRITERIA FOR UE1)2)3)

Echo height

0 – 100% > 100%

Indication to be max length of indication.disregarded regardless t or max 25 mmof length.

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Disregard.

DISTANCE AMPLITUDE

(ECHO HEIGHT)

100%

Report and repair.

PATH OF SOUND (DEPENDANT OF PROBE LOCATION)

Figure 1 Ultrasonic examination, reference curve

REFERENCE CURVE

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