material design for high strain linepipe - gedik kaynak a.Ş. · ・weld over-matching...

1Copyright © 2015 JFE Steel Corporation. All Rights Reserved. Steel Research Laboratory

Material design for

high strain linepipe

Confidential

Doc. No. FK15-06

Feb 10th, 2015

Steel Research Laboratory

T. YOKOTA


Aim of HIPER®

to increase critical buckling strain

without an increase in wall thickness

controlling microstructure

accordingly, it leads to

reduce material and construction cost

High strain linepipe: HIPER ®


Material Development Flow

ab

MicroStructureControl

StructuralAnalysis

Nano-microstructure

Mechanical propertiesMicro Mechanics

Acceleratedcooling

0

200

400

600

800

0 5 10 15 20Strain (%)

Stre

ss (

MPa

) Conventional(Q-T)

New Process(Bainite＋MA)

Rapidheating

Structure performance

Process development & control

Super-OLAC®-A HOP®

BainiteBainite--MAMA


� Deformation of buried linepipes

� Critical event of the linepipe

Fault movement

Deformation and Fracture of Linepipe

Frost heave

Thaw settlement

Bending

①Local buckling

Bending

Girth weld portion is most critical

②Tensile rupture (Weld fracture)

Seismic area

Permafrost area


Strain Capacity and Controlling Factors

・・Pipe body strain hardenabilityPipe body strain hardenability

(nn--value,value, Y/T, stress ratioY/T, stress ratio)

・weld over-matching

・misalignment

・flaw size, flaw location

・・Pipe body strain hardenabilityPipe body strain hardenability

(nn--value,value, Y/T, stress ratioY/T, stress ratio)

・D/t (diameter/thickness ratio)

・Internal pressure

Controlling factors

Tension / Weld fracture

Compression / Buckling

Mode / Critical event


Effect of SS curve on Buckling Strain

Buckling strain and n-value Stress-strain curves

σ = Aεn

n :n-value

Strain, ε

Round-house type

Str

ess

, σ

Luderselongation type

n-value (Strain hardenability)

Crit

ical

com

pres

sive

stra

in (

%)

0

0.4

0.8

1.2

1.6

0 0.05 0.10 0.15 0.20

D/t= 40-44

Round-house type

Luderselongation type

• Round-house S-S curve• High n -value

• Round-house S-S curve• High n -value

Higher buckling resistance



ab


StructuralAnalysis

Nano-microstructure


Acceleratedcooling

0

200

400

600

800

0 5 10 15 20Strain (%)

Stre

ss (

MPa

) Conventional(Q-T)


Rapidheating






How to Control Stress-Strain Curve?

� Experimentation

� Analytical study

σ

ε

Roundhouse

High n-value

� Microscopic behavior and Macroscopic behavior

� Optimization of Microstructure

Requires a lot of work and time

PP PP

“Unit Cell Model”

“Micromechanics”

by


Analysis by Unit Cell Model� Unit cell model

(Voronoi cell)

FEM meshes

Ra=1.0 Ra=4.0

6020 60 80 1000

70

80

90

0

0.1

0.2

40

Y/T

(%

)

n-va

lue

Bainite ratio (%)

n-value (cal.)Y/T (cal.)

n-value (exp.)Y/T (exp.)

� Example of analysis

Ferrite-Bainite steel


Effect of Bainite Morphology

200

300

400

500

600

700

800

0 5 10 15

Exp. (n=0.21)Ra=1.0 (n=0.03)Ra=1.5 (n=0.04)Ra=2.0 (n=0.08)Ra=4.0 (n=0.12)

Nom

inal

str

ess

(MP

a)

Nominal strain (%)

Experimental

FEM(V-BCC model)

Bainite volume fraction : 30%

� Effect of Bainite aspect ratio

• Bainite vol. fraction ~ around 30% over• Elongated bainite morphology

Round-house

High n -value

� Effect of Bainite vol. fraction

200

300

400

500

600

700

800

0 5 10 15

10%20%30%

Nom

inal

str

ess

(MP

a)

Nominal strain (%)

Bainite FEM(V-BCC model)

FerriteBainite volumefraction

Bainite aspect ratio=2.0

Ferrite-BainiteFerrite-Bainite


Analysis by Micromechanics

� Dual-phase microstructure

Harder 2nd phase

400370 980

0.30

0.25

0.20

0.15

0.10

0.05

n-v

alu

e

TS(hard phase)-TS(soft phase), ∆TS (MPa)

2nd phase ratio =50%

40%

30%

20%

10%

bainite

pearlite

martensite

Soft phase：Ferrite

Hard phase：

- Pearlite

- Bainite

- Martensite

ΔΔΔΔTS up

Higher n-valuematrix

inclusion

Plastic relaxation

Two phase

εt2

εP1

True strain

Tru

e st

ress

εP

εP2

εt

εt1

internal stress

stage 3

stage 2

stage 1

Hard phase

Soft phase

Micromechanics



ab

StructuralAnalysis


Acceleratedcooling


0

200

400

600

800

0 5 10 15 20Strain (%)

Stre

ss (

MPa

) Conventional(Q-T)


Rapidheating



Nano-microstructure




Hot leveler

Cooling bed

Furnace

slab

plate

Plate Production Line

Super-OLAC®-AHOP®

On-Line Accelerated CoolingHeat treatment On-line Process

UOE pipe forming


Plate Production ProcessT

em

pe

ratu

re

Re-crystall.temp.

CR- γ ACC

Ar3

Bainite

CR- (α+γ) ACC

Ferrite-Bainite

Accelerated cooling (ACC)

Controlled rolling (CR)

CR- ACC -HOP

Bainite-MA

Heat treatment on-line process (HOP)

MAMA

Time


MA formation

5µm

MA

Bainite

� Microstructure change

un-transformed γ

(a) after ACC

(b) HOP heating

(c) air cooling

Bainite(tempered)

ACC

HOP

Bainite

Bainite(tempered)

� SEM microstructure

Dual phase microstructure of Bainite - MA

C diffusion

Microstructure Control by HOP


TEM images of bainite-MA

2µµµµm

100nm

500nm

MA MA

MA phaseBainite-MA microstructure

Bainite (Bainitic ferrite) phase

(Nb,Mo,V)C

MA

5µµµµm


Size and Grade Availability

WT(mm)

Grade

15

20

25

30

35

X52X52 X60 X65 X70 X80 X100 X120X52

Mass produced Developed（F-B design）

Developed（B-MA design）


Supply Record of HIPER®

Total 88,137 metric ton

Chita Pipeline Project (2001)Onshore, Seismic regionX65 30”OD X 20.5mmWT 106 ton

#2 West-East Gas Pipeline Project (2008)Onshore, Seismic regionX80 48”OD X 22.0mmWT 7,500 tonX80 48”OD X 26.4mmWT 5,500 tonTotal 13,000 ton

Sakhalin 1 Project (Phase 1, 2003-2004)Onshore & Offshore, Seismic regionX60 24”OD X 15.6mmWT 6,940 tonX60 24”OD X 20.8mmWT 770 tonX60 24”OD X 30.2mmWT 5,305 tonX60 36”OD X 26.0mmWT 6,970 tonX60 48”OD X 30.0mmWT 5,360 tonTotal 25,345 ton

No.2 Suruga Pipeline Project (2001-2004)Onshore, Seismic regionX65 24”OD X 14.3mmWT 2,273 ton

Sakhalin 2 Phase 2 Project (2005)Onshore, Seismic regionX60 20”OD X 19.1mmWT 65 tonX60 48”OD X 31.8mmWT 2,825 tonTotal 2,890 ton

Sakhalin 2 Phase 2 Project (2003 - 2004)Offshore, Ice gouging regionX52 30”OD X 23.8mmWT 2,635 tonX52 30”OD X 30.2mmWT 16,575 tonTotal 19,210 ton

North Central Corridor Project (2008-2009)Onshore, Frost region X80 42”OD X 12.7mmWT 3,000 ton

Chiba-Kashima Pipeline Project (2009)Onshore, Seismic regionX80 24”OD X 14.5mmWT 281 ton

PNG Project (2010)Onshore, Seismic regionX60 32”OD X 25.2mmWT 1,850 ton

Sakhalin 1 Project (Phase 4, 2010)Offshore, Seismic regionX60 20”OD X 22.2mmWT 7,252 ton

Isewan Crossing Pipeline Project (2010-2011)Onshore, Seismic regionX65 24”OD X 15.6mmWT 4,280 tonX65 28”OD X 18.1mmWT 4,150 tonTotal 8,430 ton

#3 West-East Gas Pipeline Project (2012)Onshore, Seismic regionX80 48”OD X 26.4mmWT 4,500 ton


X120 Mill Trial (2007)

70

90

800 900 1000 1100

Y/T

rat

io (

%)

Tensile strength (MPa)

80

Round bar specimenLongitudinal direction

Bainite (B added)

Ferrite-Bainite (B-free)

Bainite (B added)

Ferrite-Bainite (B-free)

150

200

250

300

800 900 1000 1100

Cha

rpy

abso

rbed

ene

rgy

at -

30o C

(J)


ACC

ACC+HOP

Ferrite-Bainite

150

200

250

300

800 900 1000 1100

Cha

rpy

abso

rbed

ene

rgy

at -

30o C

(J)


ACC

ACC+HOP

ACC

ACC+HOP

Ferrite-Bainite

� First trial production test of X120�36”OD x 19mmWT�Design temp. –20oC

� Material design�B free-Dual phase microstructure�Online heating for Charpy energy improvement 10µµµµm10µµµµm

Ferrite

Bainite10µµµµm10µµµµm

Ferrite

Bainite

� Mech. properties

� Microstructure

OMAE2007-29561


JFE Steel’s high performance linepipe “HIPER®”won 2013 R&D100 Awards.

JFE Steel’s high performance linepipe “HIPERHIPER®®”won 2013 R&D100 AwardsR&D100 Awards.

Called the “Oscars of Innovation”, the R&D 100 Awards recognizes and celebrates the top 100 technology products of the year.

HIPERHIPER®® : High deformable linepipe for gas transmission pipeline

2013 Award ceremony2013 Award ceremony7th Nov. 2013, Orland, USA


JFE’s cutting edge linepipe products

� Martensite SS 12Cr� High efficiency stainless steel making

� Largest stainless seamless supplier

SMLS

� Large OD/ Heavy WT

� MightySeam

� Max. 26 inches OD – World largest

� High forming capability

ERW

� HIPER

(High strain capacity pipe)

� High grade (- X100)

� Sour Gas line pipe

� Heavy wall pipe

� Advanced TMCP

Super-OLAC :

Super On-Line Accelerated Cooling

HOP: Heat treatment On-Line Process

� Hybrid Forming Line of UO &

NEO PressTM

SAWL

Products Production TechnologyMill


Conclusions

914mm, 18.3mm

JFE Steel developed high strength linepipe for strain based design “HIPERHIPERTMTM” with dual-phase microstructure by applying Super-OLAC and HOPin the plate manufacturing process.

Material design for high performance linepipeinvolves not only plate products for UOE, but also hot-rolled coil products for ERW & SMLS.

24

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material design for high strain linepipe - gedik kaynak a.Ş. · ・weld over-matching...

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