Effects of microstructure and pipe forming strain on yield strength before and after spiral pipe forming of API X70 and X80 linepipe steel sheets

Seok S Sohn, Seung Youb Han, Jin ho Bae, Hyoung Seop Kim, Sunghak Lee

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

API X70 and X80 linepipe steel sheets were shaped in the form of pipe with different strains (thickness/diameter ratio) by spiral pipe forming. Tension specimens taken from steel sheets or pipes at an interval of 2.5. mm were tested, and their yielding behavior, yield strength, and yield ratio before and after forming were analyzed. In the pipes, the continuous yielding and low yield ratios were shown in the inner side, whereas the discontinuous yielding and high yield ratios were shown in the outer side. This was because the Bauschinger effect and the strain hardening effect were mainly dominant in the inner and outer sides, respectively. The overall yield strength after spiral piping was defined by the competing effect of the strain hardening and the Bauschinger effect. The competing effects depended on the microstructure and the pipe forming strains. The low-temperature transformation microstructures were preferred for achieving the larger increase of overall yield strength after pipe forming. For a specific microstructure an optimization of the yield strength can also be achieved by controlling the pipe forming strain in order to maximize the strain hardening effect and to minimize the Bauschinger effect.

Original languageEnglish
Pages (from-to)18-26
Number of pages9
JournalMaterials Science and Engineering A
Volume573
DOIs
Publication statusPublished - 2013 Jun 20
Externally publishedYes

Fingerprint

application programming interface
Steel sheet
yield strength
Application programming interfaces (API)
Yield stress
Pipe
steels
Bauschinger effect
microstructure
Microstructure
strain hardening
Strain hardening
Steel pipe
intervals
optimization

Keywords

  • Bainite
  • Electron microscopy
  • Hardening
  • Martensite
  • Sheet forming
  • Thermomechanical processing

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Effects of microstructure and pipe forming strain on yield strength before and after spiral pipe forming of API X70 and X80 linepipe steel sheets. / Sohn, Seok S; Han, Seung Youb; Bae, Jin ho; Kim, Hyoung Seop; Lee, Sunghak.

In: Materials Science and Engineering A, Vol. 573, 20.06.2013, p. 18-26.

Research output: Contribution to journalArticle

@article{f78c7769871e418d81f3ba4ec46b01f5,
title = "Effects of microstructure and pipe forming strain on yield strength before and after spiral pipe forming of API X70 and X80 linepipe steel sheets",
abstract = "API X70 and X80 linepipe steel sheets were shaped in the form of pipe with different strains (thickness/diameter ratio) by spiral pipe forming. Tension specimens taken from steel sheets or pipes at an interval of 2.5. mm were tested, and their yielding behavior, yield strength, and yield ratio before and after forming were analyzed. In the pipes, the continuous yielding and low yield ratios were shown in the inner side, whereas the discontinuous yielding and high yield ratios were shown in the outer side. This was because the Bauschinger effect and the strain hardening effect were mainly dominant in the inner and outer sides, respectively. The overall yield strength after spiral piping was defined by the competing effect of the strain hardening and the Bauschinger effect. The competing effects depended on the microstructure and the pipe forming strains. The low-temperature transformation microstructures were preferred for achieving the larger increase of overall yield strength after pipe forming. For a specific microstructure an optimization of the yield strength can also be achieved by controlling the pipe forming strain in order to maximize the strain hardening effect and to minimize the Bauschinger effect.",
keywords = "Bainite, Electron microscopy, Hardening, Martensite, Sheet forming, Thermomechanical processing",
author = "Sohn, {Seok S} and Han, {Seung Youb} and Bae, {Jin ho} and Kim, {Hyoung Seop} and Sunghak Lee",
year = "2013",
month = "6",
day = "20",
doi = "10.1016/j.msea.2013.02.050",
language = "English",
volume = "573",
pages = "18--26",
journal = "Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing",
issn = "0921-5093",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Effects of microstructure and pipe forming strain on yield strength before and after spiral pipe forming of API X70 and X80 linepipe steel sheets

AU - Sohn, Seok S

AU - Han, Seung Youb

AU - Bae, Jin ho

AU - Kim, Hyoung Seop

AU - Lee, Sunghak

PY - 2013/6/20

Y1 - 2013/6/20

N2 - API X70 and X80 linepipe steel sheets were shaped in the form of pipe with different strains (thickness/diameter ratio) by spiral pipe forming. Tension specimens taken from steel sheets or pipes at an interval of 2.5. mm were tested, and their yielding behavior, yield strength, and yield ratio before and after forming were analyzed. In the pipes, the continuous yielding and low yield ratios were shown in the inner side, whereas the discontinuous yielding and high yield ratios were shown in the outer side. This was because the Bauschinger effect and the strain hardening effect were mainly dominant in the inner and outer sides, respectively. The overall yield strength after spiral piping was defined by the competing effect of the strain hardening and the Bauschinger effect. The competing effects depended on the microstructure and the pipe forming strains. The low-temperature transformation microstructures were preferred for achieving the larger increase of overall yield strength after pipe forming. For a specific microstructure an optimization of the yield strength can also be achieved by controlling the pipe forming strain in order to maximize the strain hardening effect and to minimize the Bauschinger effect.

AB - API X70 and X80 linepipe steel sheets were shaped in the form of pipe with different strains (thickness/diameter ratio) by spiral pipe forming. Tension specimens taken from steel sheets or pipes at an interval of 2.5. mm were tested, and their yielding behavior, yield strength, and yield ratio before and after forming were analyzed. In the pipes, the continuous yielding and low yield ratios were shown in the inner side, whereas the discontinuous yielding and high yield ratios were shown in the outer side. This was because the Bauschinger effect and the strain hardening effect were mainly dominant in the inner and outer sides, respectively. The overall yield strength after spiral piping was defined by the competing effect of the strain hardening and the Bauschinger effect. The competing effects depended on the microstructure and the pipe forming strains. The low-temperature transformation microstructures were preferred for achieving the larger increase of overall yield strength after pipe forming. For a specific microstructure an optimization of the yield strength can also be achieved by controlling the pipe forming strain in order to maximize the strain hardening effect and to minimize the Bauschinger effect.

KW - Bainite

KW - Electron microscopy

KW - Hardening

KW - Martensite

KW - Sheet forming

KW - Thermomechanical processing

UR - http://www.scopus.com/inward/record.url?scp=84875064311&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84875064311&partnerID=8YFLogxK

U2 - 10.1016/j.msea.2013.02.050

DO - 10.1016/j.msea.2013.02.050

M3 - Article

AN - SCOPUS:84875064311

VL - 573

SP - 18

EP - 26

JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

SN - 0921-5093

ER -