8/11/2019 2013 CHA Seminar Presentation Dr Franz Martin Knoop
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8/11/2019 2013 CHA Seminar Presentation Dr Franz Martin Knoop
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Introduction
• Introduction• History• Development programme• Manufacturing issues relevant for sour service resistance
•• hot rolling• pipe production
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• Mechanical and corrosion test results• Summary and outlook
8/11/2019 2013 CHA Seminar Presentation Dr Franz Martin Knoop
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Introduction
' -
• extending pipe/coil wall thickness up to 25.4 mm for grades X70 and X80• steel grades with high strength and excellent low temperature toughness
• sour service resistant steel and pipe• enhancement of collapse resistance for shallow water off-shore applications•• reducing residual stresses in pipe and weld seam• improving the strain capacity of pipes for strain based design requirements
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• reduction of geometrical tolerances on steel and pipe
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History
Failures of helical welded i e
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History
Cookin reci e for sour service material
Malcolm Gray „Full Scale Testing of Linepipe for Severe H 2SService“; NACE Canadian Regional Western Conference,
nc orage, as a, e ruary — .
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Development programme
Tar eted i e ro erties R&D and commercial ro ects
DWTTHIC (base + weld) NACE SSC
Project(t)
Standard
. .
(mm) (mm) (MPa) (MPa) (J/cm 2)(% shear
area) (4 pointbend.)CAR CLR CTR CSR
SZ X60 200API 5L/ISO3183
14.0 1067 ≥ 420 ≥ 520
(base)
-40 C ≤ 5 -
No crack
X65MS ≥ 300; 0 C 85 @ at-
80% SMYS
API 5L/ISO3183.
(base) -40 C
No crack
SZ X70 200X70MS
API 5L/ISO318316.0 1016 ≥ 485 ≥ 570
≥ 300; 0 Cbase
85 @ at-40 C
≤ 5 -80% SMYSNo crack
Grade GR241 762 ≥ 50; not 80% AYS
241 CSA_Z245.1-07.
914
0 C required-
No crack
Grade800
GR448-
13.7 1372 ≥ 448 ≥ 531 ≥ 50;
-
60 @ at- - ≤ 15 ≤ 5 ≤ 2
not
Dr. Knoop Ju ly 2013, London 6.
_
(mechanical properties in hoop direction)
8/11/2019 2013 CHA Seminar Presentation Dr Franz Martin Knoop
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Development programme
Chemical com osition for R&D and commercial ro ects
Project Purpose C Si Mn P S Al Cu + Cr + Ni Mo Nb CEV (IIW) CEV (Pcm). . . . . . . . .
SZ X60 R&D 0.035 0.30 1.46 70 5 0.04 0.44 0.07 0.05 0.33 0.14
SZ X65 R&D 0.038 0.28 1.37 80 7 0.04 0.86 0.04 0.05 0.36 0.14
SZ X70 R&D 0.038 0.33 1.33 90 6 0.04 0.84 0.32 0.05 0.43 0.15
241Commercial 0.041 0.23 1.14 95 4 0.04 0.23 0.004 0.02 0.25 0.11
Grade448 Commercial 0.060 0.32 1.55 150 8 0.04 0.36 0.005 0.05 0.35 0.16
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Manufacturing issues relevant for sour service resistance
121. Blast furnace
4
2. Hot-metal mixer
3. Desul hurization facilit
5
4. BOF shop
5. Secondary metallurgy facilities
6. Continuous slab caster
6
High automatization level including closeintegration of steel plant control and supervision systemwith technical planning
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slab thickness: 250 mm
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Manufacturing issues relevant for sour service resistance
Desired quality issues Consistently applied Salzgitter’s measures to attain them
Narrow steel composition tolerances
High steel cleanliness
Continuous composition control and adjustment
Secondary metallurgy and appropriate casting procedure -
( low [O] total )
• inclusion shape and size control
• gas s rr ng + cas er w ver ca sec on
• Ca – treatment for inclusion shape control
•• low tramp element steel contents
( especially P and S )
• low H content
High slab centerline quality
• avoiding centerline segregation
Soft reduction at continuous slab caster
(C, Mn, P)
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Manufacturing issues relevant for sour service resistance
Example: insufficient ladle rinsing and unsuitable degassing
to view of US scan
Rolling direction
side view of US scan
HIC fracturesurface
Al
consistent application of LM refining measures to remove inclusionsfrom the steel melt, such as:
bottom stirring with N 2 and Ar Ouse o ap o e s e ga es or m n m ze s ag carry over
optimized Ca-treatment with Ca-wire injection; high Ca recoveryoptimized ladle rinsing procedure
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HIC cracks primarily initiated at Al-O inclusions and are traced backto slab upper half
application of caster with 2.6 m long vertical section instead of bow casters
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Manufacturing issues relevant for sour service resistance
Example: casting without dynamic soft reduction
MartensiteHIC crack at stripmid thickness
top view of US scan
side view of US scan
dynamic segment regulation (soft reduction), particularly at the point of final solidification
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’
Manufacturing issues relevant for sour service resistance
Reheating furnaces (4)
Slab sizingpressSlab sizingpress
Descaler oug ng moug ng m
Finishing train
rop s ear rop s ear Run-out table:Laminar cooling unit
descaler
Slab thickness = 250 mmr p c ness = . - mm
Strip width = 900 - 2.000 mmStrip length = 100 - 2.000 m
3 Down coilers
Dr. Knoop Ju ly 2013, London 12.
One of the world’s most modernhigh performance hot strip mills
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Manufacturing issues relevant for sour service resistance
Consistently applied Salzgitter’s measures to attain them
Desired quality issues
Continuous control and adjustment of rolling parameters
• highly planar
stri rofile e s s
m ]
Narrow strip dimension tolerances
• lowering of residual stresses in the
S t r i p t h i c k
v a r i a
t i o n
[
High strip surface quality
• prevention of surface defects e.g.
Thickness ± 60 µm
Precise temperature monitoring from furnace to coiler
Strip width [mm]slivers, roll-ins
Homogeneous strip temperature
• highly desirable acicular ferrite microstructure along the
strip length and across the strip width
• Precise stri tem erature rediction and control
• prevention of γ→α transformation
during the finishing
based on run-out table simulation• strip microstructure adjustment
without undesirable phases
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Manufacturing issues relevant for sour service resistance
Example: two-phase finish rolling / undesirable phases at strip edge area
Rolling direction
i a t i o
n
undercooled strip edges T e m p .
d e v
strongly elongated α -grains,
Martensite also observedprecise temperature monitoring and control in every process phase and section
to obtain fine- rain structure across the stri width indispensable to prevent γ→α transformation already during the finishing
to prevent undesirable phases, such as martensite
Rolling direction
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properly cooled strip edgesNO HIC cracks observed !
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Manufacturing issues relevant for sour service resistance
B = 1200 - 1500 mmα = 20 - 40
D = f B α
D = 610 - 1676 mm
submerged arc welding
Dr. Knoop Ju ly 2013, London 15.
First step: pipe forming with continuous tack welding
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Manufacturing issues relevant for sour service resistance
Consistently applied SZ’ measures to attain them
Desired quality issues
Quality controls and R&D
• use of FEM simulation methods
• consistent ualit controls and recordin of formin
controlled cold working
• during coil straightening and pipe
parameters
• continuous control of pipe geometry using a patented in-situ
• minimized springback
• optimized pre-bending of coil edges to
aser ame er con ro
• peaking below 0.8mm
avo pea ng an re uc ng oca
stress which might affect sour gas
resistivity at weld area (SOHIC)
separating forming and welding by using the HTS –processno forming stresses during welding
Material selection and welding process controls
• qualification and careful selection of coil material and
welding consumables
maximum hardness of 248 HV
Dr. Knoop July 2013, London 16.
• continuous recording and documentation of all essential
welding parameters
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Manufacturing issues relevant for sour service resistance
640
720
800
320
400
480
560
S t r e s s
,
M P a
0°
0
80
160
0 2,5 5 7,5 10 12,5 15 17,5 20
30°
45°
60°
90°
,
2 0
2.5
3.0
[ - ]
Maximum value over wall thicknessInner surfaceOuter surface
Stress strain curves at different angles Simulation of different forming strategies
0.0
0.5
1.0
1.5
.
o p s
t r e s s
h
/
h ( N F )
-2.0
-1.5
-1.0
-0.5
R e
l a t i v e r e s
i d u a
l h o
negative spring-backpositive spring-back
Dr. Knoop Ju ly 2013, London 17.
-3.0
- .
1.8E-03 1.9E-03 2.0E-03 2.1E-03 2.2E-03 2.3E-03 2.4E-03 2.5E-03 2.6E-03 2.7E-03Curvature under load [1/mm]
Relative residual hoop stress as function of the curvature under load
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R&D sour service trials: SZ X65
Mechanical and corrosion test results
Coil
Pipe
Type of samples &
R t0.5
[MPa]
Rm
[MPa]R t0.5 /R m
ADIN
[%]AAPI
[%]
DWTT @[% shear area];
CVN @[J/cm 2]
Strip 30 ° [rect.] 528 581 0.91 24 39 93 382
Pipe hoop [rect.] 483 575 0.84 24 38 75 379
Targeted API X65 grade reached reliably; excellent low temperature toughness
: spec mens were es e
Result : mean CAR value ~0.1 %
SSC (4-point-bending test): 9 specimens weretested at 85% of SMYS (383 MPa)
esu : no crac s were o serve
Full ring test: 72% of SMYS (323 MPa) for 720h in
Dr. Knoop July 2013, London 18.
NACE TM0177 solution A
Result : No indications above threshold were found byultrasonic examinations prior to and after the test
Very good sour gas resistivity
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R&D sour service trials: SZ X70
Mechanical and corrosion test results
680
700 R m 100 ]
600
620
640
660
API Samples DIN Samples
R t0.5 , R m
[ M P a
]
70
80DWTT transition
c t u r e a r e a
[
520
540
560
Coil center Rectangular samplesHoop direction
R t 0
. 5
50
60
Coil 686057 Coil 686059
S h e a r
f rTest temperature: -50
C100% shear area
6 8 6 0 5 6
6 8 6 0 5 7
6 8 6 0 5 8
6 8 6 0 5 9
6 8 6 0 6 0
Coil
-60 -50 -40 -30 -20
Test temperature [°C]
Targeted API X70 grade reached reliably; excellent low temperature toughness
HIC: 112 HIC specimens (base and weld) testedResult: mean CAR value of 2.82 % (max. 13.1 %);mean average CAR value base material: 3.62%, mean CAR value for weld specimens: 1.16%
Dr. Knoop July 2013, London 19.
ery goo sour gas res s v y, even or gra e
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Commercial ro ects: GR448
Mechanical and corrosion test results
640
660 Rt0.5
Rm
A
39
40 400
540
560
580
600
A [ % ]
5 , R
m
[ M P a
]
34
35
36
37
350
375
N a
K [ J / c m
2 ]
9 8 8 3460
480
500
520
DIN rect. sample; hoop direction
R t 0
.
30
31
32
33
8 8 9 8 0 3 0 9300
325
Mean valueTest temperature -18°C
C360 357 383 344
Targeted GR448 grade reached reliably
9 5 7 4 / 9 8
4 2
9 5 7 1 / 9 8
4 1
9 5 7 2 / 9 8
4 1
9 5 7 3 / 9 8
4 2
Heat 9 5 7 1 /
9 8 4
9 5 7 2 /
9 8 4
9 5 7 3 /
9 8 4
9 5 7 4 /
9 8 4
Heat
.,50 % Ferrite; 40 % Bainite; 10 % Pearlite
HIC: 1 set for both base material and weld per heat were tested.Result: mean CLR and CSR values of all samples 3.5 , 0.7 and 0.3 %, respectively
PipeDWTT [% shear area]; average of 2 specimens
oo sour gas res s v y esp e o re a ve y g an n con en s
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0 C -5 C -10 C -20 C -40 C -60 C
100 100 100 100 100 93100 100 100 100 95 83
Excellent low temperature DWTT results
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Summar
Summary and outlook
Large diameter helical line pipe for sour service up to X70 has been successfullyeve ope an pro uce
Critical parameters in steel production and hot rolling have been shown and their
influence has been explained by means of examples .
Well balanced microalloying and steel cleanness has been achieved in industrial trialsand commercial projects
effectively controlled and adjusted to the used chemistry an microalloyingAll necessary measures for the improvement of HIC and SSC resistance have been
Excellent mechanical properties (incl. low temperature toughness) and corrosion
resistance have been achieved
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Outlook
Summary and outlook
Next milestones are defined on basis of actual and future market needs
Growing interest for sour service resistant line pipe with heavy wall thickness up to 1’’and grades up to X70 is expected
Technical solutions re uire further develo ment
- on chemical composition of the base material,
- on welding consumables
- on further production parameters at each stage of production- and on suitable equipment at each stage of production
pes w sma er ame ers n e range o an g er wa c ness g coforming degree) need further development
Dr. Knoop Ju ly 2013, London 22.
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