2013 cha seminar presentation dr franz martin knoop

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

Dr. Knoop Ju ly 2013, London 2.

• Mechanical and corrosion test results• Summary and outlook



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


• reduction of geometrical tolerances on steel and pipe



History

Failures of helical welded i e




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 — .




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


_

(mechanical properties in hoop direction)



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




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


slab thickness: 250 mm




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)





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


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




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




’


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


One of the world’s most modernhigh performance hot strip mills




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





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


properly cooled strip edgesNO HIC cracks observed !




B = 1200 - 1500 mmα = 20 - 40

D = f B α

D = 610 - 1676 mm

submerged arc welding


First step: pipe forming with continuous tack welding




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




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


-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



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


NACE TM0177 solution A

Result : No indications above threshold were found byultrasonic examinations prior to and after the test

Very good sour gas resistivity



R&D sour service trials: SZ X70


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%


ery goo sour gas res s v y, even or gra e



Commercial ro ects: GR448


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


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



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




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


2013 cha seminar presentation dr franz martin knoop

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