Effects of microstructure and pre-strain on Bauschinger effect in API X70 and X80 linepipe steels

Seok S Sohn, Seung Youb Han, Sang Yong Shin, Jin Ho Bae, Sunghak Lee

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

In this study, effects of microstructure and pre-strain on the Bauschinger effect were investigated in two API X70 and two API X80 linepipe steel sheets fabricated by controlling the cooling condition, and their yield strength and Bauschinger parameters were measured by the tension-compression test with varying tension pre-strain. The fast-cooled steels had the higher fraction of acicular ferrite, granular bainite and martensite-austenite (MA) constituents and smaller grain sizes. The reduction in yield stress (ΔYS) of the steels having a higher fraction of MA and smaller grain sizes was higher than that of the steels having a lower fraction of MA and larger grain sizes. The ΔYS was smallest at the pre-strain of 1%, reached the maximum at the pre-strain of 2%, and then decreased with increasing pre-strain. This result could be explained by the amounts of mobile dislocations and back stress, which affected the Bauschinger effect and strain hardening effect simultaneously. Since these two effects affected the yield strength on a competing basis, the Bauschinger stress and hardening parameter were used to separately analyze these effects. It could be confirmed that the Bauschinger effect and strain hardening effect were activated at pre-strains of 1-2% and 3-4%, respectively.

Original languageEnglish
Pages (from-to)423-431
Number of pages9
JournalMetals and Materials International
Volume19
Issue number3
DOIs
Publication statusPublished - 2013 May 1
Externally publishedYes

Fingerprint

Bauschinger effect
application programming interface
Steel
Application programming interfaces (API)
steels
microstructure
Microstructure
austenite
martensite
Yield stress
hardening
Martensite
Austenite
strain hardening
grain size
yield strength
Strain hardening
bainite
compression tests
Bainite

Keywords

  • bauschinger effect
  • cold working
  • linepipe steel
  • tensile test
  • work hardening

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

Cite this

Effects of microstructure and pre-strain on Bauschinger effect in API X70 and X80 linepipe steels. / Sohn, Seok S; Han, Seung Youb; Shin, Sang Yong; Bae, Jin Ho; Lee, Sunghak.

In: Metals and Materials International, Vol. 19, No. 3, 01.05.2013, p. 423-431.

Research output: Contribution to journalArticle

Sohn, Seok S ; Han, Seung Youb ; Shin, Sang Yong ; Bae, Jin Ho ; Lee, Sunghak. / Effects of microstructure and pre-strain on Bauschinger effect in API X70 and X80 linepipe steels. In: Metals and Materials International. 2013 ; Vol. 19, No. 3. pp. 423-431.
@article{4c39857c1d5e4fbfa3bd7a7aa0dc836c,
title = "Effects of microstructure and pre-strain on Bauschinger effect in API X70 and X80 linepipe steels",
abstract = "In this study, effects of microstructure and pre-strain on the Bauschinger effect were investigated in two API X70 and two API X80 linepipe steel sheets fabricated by controlling the cooling condition, and their yield strength and Bauschinger parameters were measured by the tension-compression test with varying tension pre-strain. The fast-cooled steels had the higher fraction of acicular ferrite, granular bainite and martensite-austenite (MA) constituents and smaller grain sizes. The reduction in yield stress (ΔYS) of the steels having a higher fraction of MA and smaller grain sizes was higher than that of the steels having a lower fraction of MA and larger grain sizes. The ΔYS was smallest at the pre-strain of 1{\%}, reached the maximum at the pre-strain of 2{\%}, and then decreased with increasing pre-strain. This result could be explained by the amounts of mobile dislocations and back stress, which affected the Bauschinger effect and strain hardening effect simultaneously. Since these two effects affected the yield strength on a competing basis, the Bauschinger stress and hardening parameter were used to separately analyze these effects. It could be confirmed that the Bauschinger effect and strain hardening effect were activated at pre-strains of 1-2{\%} and 3-4{\%}, respectively.",
keywords = "bauschinger effect, cold working, linepipe steel, tensile test, work hardening",
author = "Sohn, {Seok S} and Han, {Seung Youb} and Shin, {Sang Yong} and Bae, {Jin Ho} and Sunghak Lee",
year = "2013",
month = "5",
day = "1",
doi = "10.1007/s12540-013-3007-9",
language = "English",
volume = "19",
pages = "423--431",
journal = "Metals and Materials International",
issn = "1598-9623",
publisher = "Korean Institute of Metals and Materials",
number = "3",

}

TY - JOUR

T1 - Effects of microstructure and pre-strain on Bauschinger effect in API X70 and X80 linepipe steels

AU - Sohn, Seok S

AU - Han, Seung Youb

AU - Shin, Sang Yong

AU - Bae, Jin Ho

AU - Lee, Sunghak

PY - 2013/5/1

Y1 - 2013/5/1

N2 - In this study, effects of microstructure and pre-strain on the Bauschinger effect were investigated in two API X70 and two API X80 linepipe steel sheets fabricated by controlling the cooling condition, and their yield strength and Bauschinger parameters were measured by the tension-compression test with varying tension pre-strain. The fast-cooled steels had the higher fraction of acicular ferrite, granular bainite and martensite-austenite (MA) constituents and smaller grain sizes. The reduction in yield stress (ΔYS) of the steels having a higher fraction of MA and smaller grain sizes was higher than that of the steels having a lower fraction of MA and larger grain sizes. The ΔYS was smallest at the pre-strain of 1%, reached the maximum at the pre-strain of 2%, and then decreased with increasing pre-strain. This result could be explained by the amounts of mobile dislocations and back stress, which affected the Bauschinger effect and strain hardening effect simultaneously. Since these two effects affected the yield strength on a competing basis, the Bauschinger stress and hardening parameter were used to separately analyze these effects. It could be confirmed that the Bauschinger effect and strain hardening effect were activated at pre-strains of 1-2% and 3-4%, respectively.

AB - In this study, effects of microstructure and pre-strain on the Bauschinger effect were investigated in two API X70 and two API X80 linepipe steel sheets fabricated by controlling the cooling condition, and their yield strength and Bauschinger parameters were measured by the tension-compression test with varying tension pre-strain. The fast-cooled steels had the higher fraction of acicular ferrite, granular bainite and martensite-austenite (MA) constituents and smaller grain sizes. The reduction in yield stress (ΔYS) of the steels having a higher fraction of MA and smaller grain sizes was higher than that of the steels having a lower fraction of MA and larger grain sizes. The ΔYS was smallest at the pre-strain of 1%, reached the maximum at the pre-strain of 2%, and then decreased with increasing pre-strain. This result could be explained by the amounts of mobile dislocations and back stress, which affected the Bauschinger effect and strain hardening effect simultaneously. Since these two effects affected the yield strength on a competing basis, the Bauschinger stress and hardening parameter were used to separately analyze these effects. It could be confirmed that the Bauschinger effect and strain hardening effect were activated at pre-strains of 1-2% and 3-4%, respectively.

KW - bauschinger effect

KW - cold working

KW - linepipe steel

KW - tensile test

KW - work hardening

UR - http://www.scopus.com/inward/record.url?scp=84878219422&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84878219422&partnerID=8YFLogxK

U2 - 10.1007/s12540-013-3007-9

DO - 10.1007/s12540-013-3007-9

M3 - Article

VL - 19

SP - 423

EP - 431

JO - Metals and Materials International

JF - Metals and Materials International

SN - 1598-9623

IS - 3

ER -