Welding Science and Technology_8122420737

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Copyright © 2007, New Age International (P) Ltd., PublishersPublished by New Age International (P) Ltd., Publishers

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PUBLISHING FOR ONE WORLD

NEW AGE INTERNATIONAL (P) LIMITED, PUBLISHERS4835/24, Ansari Road, Daryaganj, New Delhi - 110002Visit us at www.newagepublishers.com

ISBN (13) : 978-81-224-2621-5

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Introduction to Welding Technology 3

1.2.2 Surface Contaminants

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Solidstate

weldingISSWI

Arcwelding

(AW)

Brazing(B)

Weldingprocesses

Soldering(S)

Otherwelding

Resistancewelding(RW)

Oxyfuelgas

welding(OFW)

Thermalspraying(THSP)

Alliedprocesses

Adhesivebonding(ABD)

Oxygencutting(OC)

Thermalcutting(TC)

Arccutting(AC)

Othercutting

atomic hydrogen welding.........AHWbare metal arc welding............BMAWcarbon arc welding..................CAW

–gas.....................................CAW.G–shielded..............................CAW.S–twin.....................................CAW.T

electrogas welding...................EGWflux cored arc welding..............FCAW

coextrusion welding............CEWcold welding........................CWdiffusion welding.................DFWexplosion welding...............EXWforge welding......................FOWfriction welding....................FRWhot pressure welding..........HPWroll welding..........................ROWultrasonic welding...............USW

dip soldering........................OSfurnace soldering.................FSinduction soldering...............ISinfrared soldering.................IRSiron soldering.......................INSresistance soldering.............RStorch soldering.....................TSwave soldering.....................WS

flash welding.....................FWprojection welding.............PWresistance seam welding..RSEW

–high frequency............RSEW.HF–induction......................RSEW.I

resistance spot welding.....RSWupset welding....................UW

–high frequency............UW.HF–induction......................UW.I

electric arc spraying........EASPflame spraying.................FLSPplasma spraying..............PSP

chemical flux cutting...........FOCmetal powder cutting..........POCoxyfuel gas cutting..............OFC

–oxyacetylene cutting.....OFC.A–oxyhydrogen cutting.....OFC.H–oxynatural gas cutting..OFC.N–oxypropane cutting.......OFC.P

oxygen arc cutting..............AOCoxygen lance cutting..........LOC

gas metal arc welding.............GMAW–pulsed arc.........................GMAW.P–short circuiting arc.............GMAW.S

gas tungsten arc welding........GTAW–pulsed arc.........................GTAW.P

plasma arc welding.................PAWshielded metal arc welding.....SMAWstud arc welding......................SWsubmerged arc welding...........SAW

–series.................................SAWS

arc brazing......................ABblock brazing..................BBcarbon arc brazing.........CABdiffusion brazing.............DFBdip brazing......................DBflow brazing....................FLBfurnace brazing..............FBinduction brazing............IBinfrared brazing...............IRBresistance brazing..........RBtorch brazing...................TB

electron beam welding......EBW–high vacuum................EBW.HV–medium vacuum..........EBW.MV–nonvacuum.................EBW.NV

electrostag welding...........ESWflow welding......................FLOWinduction welding..............IWlaser beam welding...........LBWpercussion welding...........PEWthermit welding..................TW

air acetylene welding......AAWoxyacetylene welding.....OAWoxyhydrogen welding.....OHWpressure gas welding.....PGW

air carbon arc cutting..........AACcarbon arc cutting...............CACgas metal arc cutting..........GMACgas tungsten arc cutting.....GTACmetal arc cutting.................MACplasma arc cutting..............PACshielded metal arc cutting..SMAC

electron beam cutting..........EBClaser beam cutting...............LBC

–air...................................LBC.A–evaporative....................LBC.EV–inert gas.........................LBC.IG–oxygen...........................LBC.O

Fig. 1.1 Master Chart of Welding and Allied Processes


1.2.3 Protecting Metal From Atmospheric Contamination

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Inner Luminous cone: 1st reaction Outer envelope (used for pre-heating): 2nd reaction

C2H2 + O2 → 2 CO + H2 2CO + O2 = 2CO2 + 570 kJ/mol of acetylene

Total heat liberated by 1st reaction H2 + 1

2O2 = H2O + 242 kJ/mol

(227 + 221) = 448 kJ/mol C2H2 Total heat by second reaction = (570 + 242) = 812 kJ/mol of C2H2

Total heat supplied by the combustion = (448 + 812) = 1260 kJ/mol of C2H2

Fig. 2.2 Schematic sketch of oxyacetylene welding torch and gas supply [1].

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Welding Science 57

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Welding Science 61

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(a) Initial crystal formation (b) Continued solidification (c) Complete solidification

Fig. 5.1 Pattern of solidification of metals

Fig. 5.2 The three most common crystal structures in metals and alloys. Left: facecentred cubic (FCC) Centre: Body centred cubic (BCC) and right: hexagonal closepacked (HCP).

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Thermal and Metallurgical Considerations in Welding 99

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Sub-zero temperature range

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°C

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300

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100

1400

1200

1000

800

600

400

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11

32

38

40

40

41

43

50

55

57

66

66

Time of transformation

Seconds Minutes Hours

1 2 4 8 15 30 –1 2 4 8 15 30 1 2 4 8 15

M temperaturef

Martensite

Martensite formsinstantly from austeniteon cooling

Martensite formsinstantly from austeniteon cooling

M temperatures

Austenite

Bainite forming from austenite

Bainite forming from austenite

Featherybainite

Fine pearlite

Nose

Austenite

A temperature1Starts Ends

Transformationat 705 °C(1300 °F)

Austenite

Coarse pearlite

Pearlite

Bainite

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tem

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Fig. 5.5. The TTT diagram for the transformation of austenitein a euctectoid (0.8% carbon) plain carbon steel.

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Mf = Martensite finish temperature

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Weld

HeatHeat HeatHeatHeatHeat

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°C

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ting

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Time Time

Lowest temperaturefor metallurgicalchange

(b) Fusion boundary (c) Outer boundaryof heat-affectedzone

Fig. 5.6 Variation of temperature with time at different distancesfrom the heat source (b) fusion boundary (c) outer boundary of HAZ

5.2.1 Weld-Metal and Solidification

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Weld (hot)

On cooling,

tries to go to this

Plates(cold)

Compressive Compressive

Tensile

Weld is stretched by plates.Tensile stresses in weld.Compressive stresses in plateon either side of weld.

Fig. 5.13 Deformation of a weld metal element during cooling.


3 mm

cb

a

5 mm

45°

Direction oftransverseshrinkage

t = 12 mm

Fig. 5.14 Estimation of transverse shrinkage in ‘T’ butt joint

w

Single-V Double-V

Averagewidth

Fig. 5.15 Transverse shrinkage in ‘V ’ butt welds.

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Afterwelding

Original

(a) Changes in shape resulting fromshrinkage which is uniform throughout the thickness

(b) Asymmetrical shrinkage tends toproduce distortion.

Fig. 5.16 Change in shape and dimensions in butt-welded plate.

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Neutralaxis

(a)

Original preparation

2t/32ndside

1stsidet/3

t(b)

(c)

10° 10°

Fig. 5.17 Edge preparation designed to reduce angular distortion

(a) Double-V joints balance the shrinkage so that more or less equal amounts of contractionoccur on each side of the neutral axis. This gives less angular distortion than a single ‘V’.

(b) It is difficult to get a completely flat joint with a symmetrical double ‘V’ as the first weld runalways produces more angular rotation than subsequent runs; hence an asymmetrical prepa-ration is used so that the larger amount of weld metal on the second side pulls back thedistortion which occurred when the first side was welded.

(c) Alternatively, a single-U preparation with nearly parallel sides can be used. This gives anapproach to a uniform weld width through the section.


Direction of welding

Longitudinaldistortion

Fig. 5.18 Longitudinal bowing or distortion in a butt joint

12

34

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Fig. 5.19 Sequences for welding short lengths of joint to reduce longitudinal bowing

Longitudinla distortio

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Fig. 5.20 Longitudinal bowing in a fillet-welded ‘T’ joint

(a) Distortion causedby fillet weld

(b) Use of presetting to correctdistortion in fillet welded 'T' joint

1st weld2ndweld

1 3 2

(c) Distortion offlange

1 = plate centre-line beforewelding

2 = plate centre-line afterfirst weld

3 = plate centre-line aftersecond weld

Fig. 5.21 Distortion in fillet welding of ‘T’ joints


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16 17 18 19 20Chromium equivalent = % Cr+%Mo+1.5×%Si+0.5×%Nb

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Length of weld

Field weld symbol

Pitch (center-to-centerspacing) of welds

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Weld-all-around symbol

Reference line

Number of spot orprojection welds

Elements in thisarea remain asshown when tailand arrow arereversed

Depth of preparation size orstrength for certain welds

(Tail omittedwhen referenceis not used)

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Size of filletin inches

Depth ofpreparation in inches

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Fig. 8.7 Size of fillet welds

8.2.1 Steps in Preparing Welding Procedure Sheets

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D 7/1/1

8.4.3 Fatigue as a Joint Preparation Factor

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Fillet welds Butt welds

Lap Butt

Tee fillet Tee butt

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t

!!"

)H*<;*006<6<0('@)

2)!;

$ 0 ,"

$ :

$ @

')!;

$ 0≤-

$ :

$ @

$ I,"

")!;(;

$ 0I" ,

$ @

$ I"/

!#$

• A

• )

• *

)

g

g

Low strength

Better strength

Fig. 8.10 Factors affecting joint preparation (contd.)

Incomplete fusion(superiority is lost)

defect


Distortion

Distortion

Penetration

Backing bars in areasunaccessible for gouging

Backing strip

Backing providedby the part. Italso alligns.

Constraineddistortion canlead to cracks

Fig. 8.10 Factors affecting joint preparation


"#% & !!

0≤1

)C

αI-3GI,$"

I,$"

& ' ()*+% (%! "

< I3

γC

+

C

=

αI,,G βI3$,G

β I#3$#,G

I3$,

I,$"

0

αI#,GI-

αI"3GI-

αI 3GI1,

Fig. 8.11 Single V preparations

a

g

s

g

g

g

g a

b2

b1

s2

s1

a

a

g


,-"&.)/

• 0

01"#% ) & % !!

0≤1

αI,3GI-$"

I-$"

2

=

(

0-")2.)/

αG

#, -"

", /

, 1,

a

g

a

gs

g

a

n

g

a

g

a°453020

‘g’ mm66

9.5

Fig. 8.12 Single bevel preparation


31"#% $ !!

0

C

7

α0

41"#% !!

0

0

J1A

!*

I#3G

%α I 3G&?I

1$"/αI 3GII-$" γI1,$

Fig. 8.13 Single U preparation and single J-preparation

Suitable only forout-side corner

b2

b1

25 – 20°

5 – 10°

a2

a1

Asymmetric prep. forhorizontal-verticalwelding

Access and economyin deep groovesIncrease = 30 – 40°

remains 20°1

2

a

g

g s

Thickness t

ag

= 19.5 – 38 mm= 20, s = g = 1.6 – 3.2 mm= 6.3 to 9.5 mm

g

s

a

g


a = 20 – 25°

Fig. 8.14 Single J preparation

51($)% & !!

P

P s

g

g

at = 12 50 mm= 60° s = 0 – 1.6 g = 1.6 – 6.3 mma

–

b1 = 10 – 15°

b2 = 45 – 40° b2

b1

a

a

sd2

d1

Unequal preparation for jointsfixed in flat position reducingoverhead welding volume.

Asymmetric preparationfor horizontal-verticalposition welding

Requires less weld metalBalanced welding sequenceControlled distortionLarge solid angleBack gouging needed forefficient high quality joint

g

Fig. 8.15 Double V preparation

)

=

2*


61($)% ) & % !!

0I1,

αI,3$,,GI3-

I--"

6

!C

2

C=

Fig. 8.16 (a) Double bevel preparation

Fig. 8.16 (b) Double bevel preparation

1($)% $ !!

a

g

s

g

a

gs

d2

d1

b2

b1

b1 = 5 to 10°b2 = 25 to 20°

t

s

g

38 mm= 20°= 1.6 to 3.2 mm= 1.6 to 3.2 mm= 6.3 to 9.5 mm

³a

g

Fig. 8.17 Double U preparation

s g

g

a

( )a

sd2

d1

a

a

(b)


71($)% !!

2 D

≥"/

αI, ,GII-"

γI1,

Fig. 8.18 Double J preparation

-1'8 ( !!"

@* 7 *

) C

Combination of V and bevel where welding

can be done easily from both sides.

Fig. 8.19 Mixed preparations

)#

0 7 =

07/ 30

0

4 0

K 5 K 5:

=(7/

s

g

g

a


Flat FlatHorizontal Vertical

Vertical Overhead Overhead Horizontal

Fig. 8.20 Welding positions for butt and fillet welds

Line of root

SlopeSlope

Fig. 8.21 Diagram to illustrate weld slope

:

! (

7/

Rotation of weld 0°


150°150°

90°90°

Rotation of weld 90°Rotation of weld 45°

45°45°

180°180°


Fig. 8.22 Diagrams to show weld rotation

0

$ (.9 + 3G

+ 3G


$ 9 + 3G#,G

+ 13G

$ :;<&9 + 3G

3G + 13G

$ &9 + #,G

13G

$ 29 + #,G

13G

*!' "'#

!-,

0

+ !"#

:)

(

!

6

7+)F !

!

0 !

!

0

0

( 5

0

!0!

)(

!

!


"$''!*+:!9

0

Materialthickness Manual metal arc Manual CO

DIP transfer2 Manual CO

spray transfer2 Mechanised CO2 Submerged arc

Process

20 S.W.G.

16 S.W.G.1/32 in.

1/8 in.1/16 in.

3/16 in.60°60°

1/16 in.

1/16 in.

1/4 in.60°60°

1/16 in.

1/16 in.

1/32 in.

3/8 in.60°

60°-70°

1/16 in.

1/16 in.

1/16 in.

40°-50°

1/16 in.

40°

1/16 in.

40°

1/16 in.

1/2 in.60°

60°-70°

3/32 in.

3/32 in.

40°-50°

1/16 in.

40°

1/16 in.

40°

1/16 in.1/16 in.

3/4 in.

60°60°-70°

1/8 in.

1/8 in.

50°

1/16 in. 50°

1/8 in.

40°

40°

1/4 in.

40°

40°

1/4 in.

1 in.

60°-70°

1/8 in.

50°

50°

1/8 in.

60°-70°

60°

1/16 in.

60°

40°

40°

1/4 in.40°

40°

1/4 in.

1½ in.

60°-70°

1/8 in.

50°

50°

1/8 in.

60°-70°

60°

60°

1/2 in.

60°

60°

1/16 in.

40°

40°

1/4 in.

3 in.

20°

1/8 in.

50°

50°

1/8 in.

60°

1/16 in.20°

1/4 in. r

60°

30°

1/2 in.

30°

1/4 in. r

30°

1/4 in.

30°

1/4 in. r

1/16 in.


%& :

%& < B

%& F L

%& F

%& 0

%& 6

%&

%& < %& <

%& 2

%& )% &

%& 6

%& :

%& F

%&

%& )=

%& A

%& 2

%& '

%&

%& 6

%& 0

%& @

%& : !

%& 0!

%& F

%& F

%& 6

% & 6

8.7.1 Type of Joints

0+ 0

7/ "

+

4

%& F

%& : L


%& :

%& D

+

%& L !

%& 2

(A) (B)

(D) (C)

(E) (F)

Fig. 8.23 Major types of joints: (A) Square butt weld (B) Square tee-joint and fillet welds(C) Cruciform joint with four fillet welds (D) Lap joint with single fillet weld (E) Full open corner joint with fillet welds (F) Edge joint with edge weld.

C 7.1$.1

%2.&

8.7.2 Welding Parameters

0

=

!0

%& ! =

*


!A

=

A=!

Included angle

Angle of bevel

Root face

GapGap

Root radiusIncluded angle

Angle of bevel

Root face

GapGap

Included angle

Angle of bevel

Root face

GapGapRoot radius

Land

Fig. 8.24 Terms pertaining to typical weld preparations

7

=

0=

# %-3"& ",

%.3/&

, -3"

.3/

0 =

(C+

= (

0 %-/&


Weld width

Weld face

ToesToes

Toes

Weld face

Toes

Leg (length)

Weld width

Weld face

Toes

Leg

(Length)

Fig. 8.25 Term pertaining to welds

Design throat thickness

Actual throat thickness

Design throat thickness

Fig. 8.26 Actual and design throat thicknesses of welds

( =

%&(

!

=

%&"#0

242 42+ ## 2

: 2%0#"..&


:+

5 42

%&$; 7

=

0

(

+(

0

0

0 +

7

! =

:

=(

!

%&% !

2 !

A !+

%& %

:

+

$

: .

!' !"#

):

0 =

7/ .

@

+

( ):

(FF:

(

):

F +


+(

Fig. 8.27 Joint and positions suitable for SAW

Second pass

Backing pass

Second pass

Backing pass

Fig. 8.28 Base metal backing for SAW

)):

!%+&(

): !

(): =

0

0

0!

8.8.1 Weld Backing Techniques

0 !%&;L

% &)L%"&: L%#&;L%,&2L%-&7+

L%.&;

-)=/07/ /

0 ! !

2

0


,"=/(

7/ 1(

0

Fig. 8.29 Structure backing for SAW

Fig. 8.30 Weld backing for SAW

0>=/0

2' + %7/"3&

(

0 !(

+

0

3)/0

0

7/"( (

)

(- #/

(

L

4+=/2 7/" (

+

?

0L

(

7

0

(

(

2+


5 =/7/"" )+

+0

+0!

): D

Backing strip

Fig. 8.31 Backing strip for SWA

(A) (B)

Fig. 8.32 Copper backing for SAW: (A) V-groove butt; (B) Square butt

6)/ 2

*)0+

A3,

30

0(MF(M

;

0 +

+

8.8.2 Butt Welds

0

0

:! 0

0/

=-("!=..=/

! "

&

!' & B

- # ",3 " ,3

3 # #33 # #

# " ,33 "3 #3

"- " -,3 " "3


D7/"#

0 0/

6 . !

(

6 0/

Fluxbacking

Flexiblesheetmaterial

Inflatedhose

Trough

Paperinsert(Optional)

Plate

Fig. 8.33 A method of producing flux backing for SAW

g

t

Steel back-upSteel back-up

Fig. 8.34 Joint fit-up for butt welds in sheet metal

=,("!=..=/

( ! " &

&

B

!' B

- 3$3/ " #,3 , #,

3 3$3/ " ,33 . ""

# 3$- " ,,3 . ,

"- 3$- " -,3 / 3

#/ - ,3 /,3 " ,

-# " ,3 133 ""

1, " ,- 1,3 "" 3

. #/ ,- 333 "# /


6 -#$,1 !

7/",0 (

6 0/"

tSecond pass

Backing pass

Close fit-up

Fig. 8.35 Square butt weld in two passes, one from each side

9.5 MM

3.2 MM

19 MM

2ndpass

1st pass1st pass

2nd pass

25.4 MM

9.5 MM

9.5 MM

Fig. 8.36 Parameters for two-pass 19 mm and 25.4 mm t butt welds

=0(.?@=.

)

! " & ! " &

& B & B

-# #3 #., 1 3 #3 ,., " 3

1, #3 ,33 "" # #3 /,3 ", #

. ,3 .33 ", ,3 1,3 "-

,1 ,3 133 "- 1 ,3 1,3 "- 1

0 + 1 ,#

-3GC

7/"-6 0/#


=3(-7,43=.

*+ ,-.

7

, ,

2%42N& .33 /,3

CC ", ",

) B ,,

)

, ,

2%42N& 1,3 333

CC "- "-

) B - .

:C

7

/".0 " "/0/,

( +

0

0

! !

70°

60°

16 MM

9.5 MM

3rd pass

2nd pass

1st pass

32 MM

38 MM

1st pass

2nd pass

3rd pass

90°

70°

16 MM

12.7 MM

Fig. 8.37 Parameters for three-pass 32 mm and 38 mm t butt welds


=4(0,0=.

/

! " & ! " &

& B & B

" , /,3 ", ,, , 333 "- ,

/" , 333 "- # , 333 "- #

! " &

& B

, /,3 ", #

, 1,3 "# "

7

! +

7- ,# "/+

7/"/7 #

:)

.B# ,,3 /C0)-

,# "/, -

)

60°

6.4 MM

3.2 MM

Fig. 8.38 Joint fit-up for multi-pass butt weld

, !(-

F(MB2'

0

7

!

:

)


!

!

0 !

5

(

0===

) ==

L

!

== != ' ===

0

=

(

+

==-# 1, (

==7+

+ "

== 7

0/-

=5#'#A+,.

%

) "-3"#C- )

4 ! L "/C

) O

=

,B

) 31C )

6 ! 3C

) O

=

,B

" )%&!

0

7 0/-

%&(


.!#

/ : A

/ :

()' :)

/" : P4

4

/# : P:+

48 9 8 9

/, ? P:

/- :8 9P:

P

/. 4 )

// ? P)

%& = %&2

%&: %&

%& %&:

/1 ; ):

: ):

/3 + ):

%&;

%&7+

/ ;+0(M F(M

180

(a) Undercut (b) Cracks

(c) Porosity (d) Slag inclusions

(e) Lack of fusion (f) Lack of penetration

Fig. 9.1 Typical weld defects

Weld Quality 181

!

"#$%% &%'()*

*%&!

!

!

+ "

, -

)

.

/

! 0

Crater cracks

Arc strike Toe crack

Underbead crack

Longitudinalcracks

Transversecracks

Toe crack

Fig. 9.2 Types of cracks in welded joints


*%1

!

!

" )

.

2

" )!

&3 +

1#

42

$5+ +

(

'3

67

!

!+

+ 8

" ##

!

Weld Quality 183

A B

Fig. 9.3 Types of lack of fusion

$ #

!

9

%# &#

5+ :

*%$*%(

!

0

")

")9

Reinforcement of buttsmore than 3.2 mm(1/8 in.) is excessive

Lack of filler metal

Fig. 9.4 Excessive reinforcement, Lack of filler metal


A B

C

D

Size Size

45°

Desirable fillet weld profiles

Convexity Cshall not exceed0.15 + 0.03 in.

SS

S S

C

Acceptable fillet weld profiles

Size Size Size Size Size

Insufficientthroat

Excessiveconvexity

Excessiveundercut

Overlap Insufficientleg

Defective fillet weld profiles

C

Fig. 9.5 Desirable, acceptable and defective fillet weld profiles

")

")

'#

: *%'

!

Weld Quality 185

a. No corrosion b. Uniform c. Galvanic d. Erosion e. Fretting f. Crevice

More noblemetal

Flowingcorrodent

Cyclicmovement

Load Metal ornon-metal

g. Pitting h. Exfoliation

i. Selective leaching j. Intergranular k. Stress cor-rosion cracking

l. Corrosionfatigue

Fig. 9.6 Types of corrosion commonly found in metals and alloys

9.8.1 Galvanic Corrosion

! + !

;

.

! *%6

Large cathodic regionsSmall

anodic region

Large anodic regionsSmall cathodic region

A A

Regions where attack may be serious

Fig. 9.7 Galvanic corrosion in a welded join

Top: weld Metal less noble than base metal

Bottom: Weld metal more noble than base metal


9.8.2 Crevice Corrosion

. 0

<+

+!

9

9.8.3 Intergranular Corrosion

!

.

+

'(=>.!

'(=>.

!

9.8.4 Stress Corrosion

<

+

. !

!

0

") #

") .

")

")

")

") 3 " ) !

+

")

< 0

Weld Quality 187

APPEARANCE TYPE OF CORROSIONWeld metal

Base metal

a. Uniform

b. Base metalcorrosion

c. Weld metalcorrosion

d. Base metalhigh-temp. HAZcorrosion

e. Base metallow-temp. HAZcorrosion

Fig. 9.8 Types of corrosion in a welded joint

!# (

"*%?)!

"*%?) "*%?)

@A:

@A

"*%?)

@A "*%?)

9.9.1 Factors Affecting Corrosion Resistance of Welded Joints

& <

1 !

4

$ "

(

' 9


!

+

B

B

B " )

B

B

B

B

! *%?%?%?**

%? %?

!

%& #+ :

%1

%4

%$ :

:

%( C 3

189

!

"

!

#

!$

10.1.1 Tension Tests for base metal

$

10.1.2 Weld Tension Test

"

%&'&

$ %&'&

%&'(


Longitudinal weldspecimen

Weld 8"

Gage length

1.5"2"

Both plate - typespecimens have iden-tical dimensions

18" min

t

Transverseweld specimenBase metalAll weld

metal

0.252 or 0.505"diam round specimensdepending on t

Fig. 10.1 Typical test specimens for evaluation of welded joints (dimensions in inch units)

T

f

f

W

6.4

6.4

W = 38.1 ± 0.3T = 8 mm. approx.

25.4 approx.

50.8

–50.

6R

6.46.4

Machined by milling

(a) Transverse-weld tension specimen

25.4 ± 1.6

25.4 8

38.1

76.2 63.5 76.2

25R

Machined by milling

(b) Longitudinal-weld tension specimen

Fig. 10.2 Tension test specimens with dimensions in mm

Testing and Inspection of Welds 191

76.231.8

25.4 0.13

4.6 R

9.5

6.4 ± 0.13 6.4

Specimenlocation

(c) All weld metal tension specimen

Fig. 10.2 Tension test specimens with dimension in mm

#

!

)

#

* #

*+

!

10.1.3 Tension-shear Test

$

,%&'-.

/

#

"

0 1"


A. B.

D. C.

After welding After machining

Fig. 10.3 Various types of tension-shear specimens

10.1.4 Tension Tests for Resistance Welds

#

%&'2

"

"

! ,%&'3.

4

!&,''2.

"

,.

! " 25,'&6 .


"

Edges as sheared Direction ofrolling (preferred)

Spot-weld centeredas shown

Fig. 10.4 Test specimen for tension shear

a.

b.

Thickness up to 4.8 mm (0.19 in.)

Thickness over 4.8 mm (0.19 in.)

Fig. 10.5 Cross-tension test

0


Fig. 10.6 Test jig for cross-tension specimens

78 7!!$0&&

"

%&'3 "!

&,''2.

%&'1 "26%

&'9 "


%&'9,.

"

*

"

(a) (b)

Fig. 10.7 Jig for cross-tension test (t > 4.8 mm)

: %&'5,.

Fig. 10.8 (a) Bend tests


Roller supportor greasedshoulders

A1"4 R

t

1"4A = 1 when t

1"2

A = 2" when t > 1"2

Initial bend for free-bend specimens

Final bend forfree-bendspecimens

Shoulder

Plunger

Roller (alternate)

Specimen

Die

Fig. 10.8 (b) Typical fixtures for free bend testing (top) and guided bend (bottom).(for SI equivalents U.S. customary values)

10.2.1 Procedures of Preparing Test Sample

8 ;

& 0 3'5

,%&'6.) "

$291

( $

- 091(,-.,%&'&'.)

" % $<!

2 =


3 0"

,.)

,."

,.$

,.8

1 $

7 :

Cut

Cut5.08 cm(2 in.)

Fig. 10.9 Cutting test samples

Fig. 10.10 Sample cut into equal pieces

10.2.2 Guided Bend Tests

"$

>

$ ;

!$ ! $ $ ? !

8 ! 8@&'616

$<A $ < A 0 :

8 >


8# 8 #$ !8

7%

%&'&&

" " 9'-"4(,&' ''.

Tapped hole to suittesting machine

As required

118

14

34

34

378

2234

CC

99

712

514

412

R34

3 4

34

12 11

8

634

18

B D

Shoulders hardenedand greased

As required

Malemember

Femalemember

Hardened rollers

diameter

may be substitutedfor big shoulders

112

Materialyield strength–psi

–A–(inches)

–B–(inches)

–C–(inches)

–D–(inches)

50,000 and under

55,000 to 90,000

90,000 and over

2 1

112

34 23

81 316

278

1 716

212 11

4 338

11116

AA

Fig. 10.11 Typical bend test jig. (All dimensions are in inches)

10.2.3 Preparing the Sample for Bend Testing

/

,%

&'&(. ,%&'&-.%

,%&'&2.

"

-&9 ,%&'&3.

", .


Discard bothend pieces

min38

1211

211211

21

124

124

10²10²

(A)

Fig. 10.12 Flat plate test. (All dimensions in inches)

Tack weld

Flat

Horizontal38 min.

2G4G

3G

1G

66 55 55

(B)

Fig. 10.13 Fixed box pipe all position test. 1G-1 Flat position root bend 1G-2 Flatposition face bend 2G-3 Horizontal position root bend 2G-4 Horizontal position facebend 3G-5 Vertical position root bend 3G-6 Vertical position face bend 4G-7 Over-head position root bend 4G-8 Overhead position face bend.

as welded

Fig. 10.14 Reinforcement removal


Center lineof weld

Length as perspecification

Grind scratches

Grind scratches

Radius cornersRadius corners

Fig. 10.15 Prepared specimen for bending

10.2.4 Root and Face Bend Specimens

% ,%&'&1

&'&9.* !$&'' B

$ #

-(, " ".

# -(

% 1= #

-(

Top of pipe for 5Gand 6G positions

Face bend

Root bend

45°

Root bend

Face bend

Pipe wall 3/8 in. and under

Discard bothends

RootbendRoot

bend

FacebendFace

bend

Fig. 10.16 (a) Pipe root and face. Plate root and face


Root Bend

Face Bend

Side Bend

Face bendRoot bend

Side bend

Weld joint

Fig. 10.16 (b) Relative orientations of face, root, and side-bend tests from a welded plate

Fig. 10.17 Root bend and face bend on small-diameter pipe sample

!"#" $

C &'&

> @ <

7

10.3.1 Magnetic Particle Inspection

<

" "

# $


:

%&'('

Alternatingcurrentcoil

Shaft beingdemagnetized

Fig. 10.18 Alternating current coil

Magnetic fieldaround an electriccable

Magnetic field

Defect

Electric current

Fig. 10.19 Circular magnetization of a shaft


Electric current

Magnetic field

Defect

Magnetic field

Electric coil

Defect

Fig. 10.20 Longitudinal magnetic inspection

10.3.2 Radiographic Inspection

7 B

B

=

D

"

D

"@

B

%&'((

"


Magnetizingcurrent

Magnetic linesof force

150 to 200 mm

Weld

Fig. 10.21 The prod method

TargetElectrons

Focusingcup

Filament

CathodeAnode

X-rays

Fig. 10.22 Operation of an X-ray device

/ " B

#

"

%&'(- B B

Glass envelope Electron stream filament

Cathode

Focusing cupWindow

X-raysTungsten

target

Anode

Fig. 10.23 Construction of an X-ray tube


B

B

B

B

/

,B .

"

10.3.3 Ultrasonic Inspection

) #"

&3 '''

#

"

"

,07.

%&'(2

07 " %

&'(3

Time

Horizontalsweep

Back surfacereflection

Discontinuity

Initial pulse

Focusand acceleration

Horizontaldeflection plates

Elect

ron

beam

Electrongun

Verticaldeflection plates

Glass tube

Horizontal sweep line

Viewing screen

Fig. 10.24 Cathode ray tube Fig. 10.25 Cathode tube construction

1'&'''

07


%

"

"

" "

!

> # A @

$ " 8

@ $ " AC / "

"

C

< $ " 78 / "

" =

< 0

0

C

7 8 0 A

" = $

0 " = :

"

7

"

) > 8

7

"

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Fundamentals of Underwater Welding Art And Science 247

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(a) Ship repairs

Fig. 15.3 Use of Hyperbaric chambers (Habitat welding)


(b) Hot-tap welding of pipelines

Fig. 15.3 Use of Hyperbaric chambers (Habitat welding)


Umbilical gasand electricity cable

Dryhyperbaricchamber

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Weld-ball

Seal

Pipeline

Removable floor andwall sections

(c) Making Weld-ball pipeline joint

Fig. 15.3 Use of Hyperbaric chambers (Habitat Welding)

15.3.2 Local Chamber Welding (See Figs. 15.4, 15.5 (b) and 15.6)

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(a) Portable dry spot (PDS) welding

(b) Example 1Repairing a damaged riser

A. Cut is made below the damaged area,noting location of riser clamps,and the stub and cleaned.

B. Damaged section is removed whilereplacement assembly is madeready on the surface.

C. New section is lowered over theriser stub and the upperconnection is made.

D. Transparent box is put in place,water avacuated, and the weldmade.

(b) Stages in the repair of damaged riser using Local Dry Environment ‘‘Hydrobox’’

Fig. 15.5 Underwater dry welding


PlatformReplacementriser

Air

Water

Gasconnexions

Hydrobox

Weld collar

Fillet weldmade with Hydrobox

Old riser

Hydrobox in use for a Vertical Riser Repair

Fig. 15.5 (c) The Hydrobox Showing Schematic Arrangement for makinga Riser Repair (details) (Kirkley, Lythal, 1974)

Fig. 15.5 Underwater dry welding

15.3.4 Wet Welding

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Example 2Use of universal assembly

B. Riser is rotated until it iswithin the misalignmenttolerance of 15°.

C. Ball half of the connectoris placed on the pipelineend.

D. Connector halves are movedtogether and a transparentbox placed to cover the weldareas at the joint and therear of the ball half.

Planview

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Pipe

Weld-ball

Pipe

Welds

Fig. 15.6 Use of universal assembly being welded in adry chamber (transparent perspex) (Kirkley, Lythal, 1974)

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Welding Science and Technology_8122420737

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