Fabrication of bimodal-grained Al-free medium Mn steel by double intercritical annealing and its tensile properties

Jeongho Han, Seok Hyeon Kang, Seung Joon Lee, Young Kook Lee

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The objectives of the present study were to develop the bimodal-grained microstructure in a medium Mn steel without the addition of Al only through a thermo-mechanical process, and to systematically investigate the relationship between the bimodal-grained microstructure and yielding behavior. The cold-rolled Fe-7Mn-0.05C (wt.%) steel with deformed α′ martensite was annealed twice with different temperatures and holding times. When the cold-rolled specimens were first-annealed at 660 °C for 4 h-22 h, the specimens showed a dual-phase microstructure consisting of globular-shaped ferrite (αG) and thermally induced α′ martensite at room temperature. Whereas the sizes of both αG grains and α′ martensite constituents increased with increasing the first annealing time, both the volume fraction and the chemical concentration of each phase were insignificantly changed. When the first-annealed specimens were annealed again at 640 °C for 5 min, the specimens exhibited bimodal-grained structures with coarse αG and ultrafine lath-shaped ferrite (αL) and retained austenite (γL). The coarse αG came from αG pre-existing in the first-annealed specimen; the fine αL and γL formed by the α′ martensite to γ diffusive reverse transformation. The second-annealed specimens exhibited a transition of yielding behavior from discontinuous yielding with yield-point elongation (YEL) to continuous yielding without YEL due to the coarsening of αG grains with increasing the first annealing time up to 22 h.

Original languageEnglish
Pages (from-to)580-588
Number of pages9
JournalJournal of Alloys and Compounds
Volume681
DOIs
Publication statusPublished - 2016 Oct 5

Fingerprint

Steel
Tensile properties
Martensite
Annealing
Fabrication
Microstructure
Ferrite
Elongation
Coarsening
Austenite
Volume fraction
Temperature

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

Cite this

@article{c0c1c9f87c8e4955a14901186adef67a,
title = "Fabrication of bimodal-grained Al-free medium Mn steel by double intercritical annealing and its tensile properties",
abstract = "The objectives of the present study were to develop the bimodal-grained microstructure in a medium Mn steel without the addition of Al only through a thermo-mechanical process, and to systematically investigate the relationship between the bimodal-grained microstructure and yielding behavior. The cold-rolled Fe-7Mn-0.05C (wt.{\%}) steel with deformed α′ martensite was annealed twice with different temperatures and holding times. When the cold-rolled specimens were first-annealed at 660 °C for 4 h-22 h, the specimens showed a dual-phase microstructure consisting of globular-shaped ferrite (αG) and thermally induced α′ martensite at room temperature. Whereas the sizes of both αG grains and α′ martensite constituents increased with increasing the first annealing time, both the volume fraction and the chemical concentration of each phase were insignificantly changed. When the first-annealed specimens were annealed again at 640 °C for 5 min, the specimens exhibited bimodal-grained structures with coarse αG and ultrafine lath-shaped ferrite (αL) and retained austenite (γL). The coarse αG came from αG pre-existing in the first-annealed specimen; the fine αL and γL formed by the α′ martensite to γ diffusive reverse transformation. The second-annealed specimens exhibited a transition of yielding behavior from discontinuous yielding with yield-point elongation (YEL) to continuous yielding without YEL due to the coarsening of αG grains with increasing the first annealing time up to 22 h.",
author = "Jeongho Han and Kang, {Seok Hyeon} and Lee, {Seung Joon} and Lee, {Young Kook}",
year = "2016",
month = "10",
day = "5",
doi = "10.1016/j.jallcom.2016.04.014",
language = "English",
volume = "681",
pages = "580--588",
journal = "Journal of Alloys and Compounds",
issn = "0925-8388",
publisher = "Elsevier BV",

}

Fabrication of bimodal-grained Al-free medium Mn steel by double intercritical annealing and its tensile properties. / Han, Jeongho; Kang, Seok Hyeon; Lee, Seung Joon; Lee, Young Kook.

In: Journal of Alloys and Compounds, Vol. 681, 05.10.2016, p. 580-588.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Fabrication of bimodal-grained Al-free medium Mn steel by double intercritical annealing and its tensile properties

AU - Han, Jeongho

AU - Kang, Seok Hyeon

AU - Lee, Seung Joon

AU - Lee, Young Kook

PY - 2016/10/5

Y1 - 2016/10/5

N2 - The objectives of the present study were to develop the bimodal-grained microstructure in a medium Mn steel without the addition of Al only through a thermo-mechanical process, and to systematically investigate the relationship between the bimodal-grained microstructure and yielding behavior. The cold-rolled Fe-7Mn-0.05C (wt.%) steel with deformed α′ martensite was annealed twice with different temperatures and holding times. When the cold-rolled specimens were first-annealed at 660 °C for 4 h-22 h, the specimens showed a dual-phase microstructure consisting of globular-shaped ferrite (αG) and thermally induced α′ martensite at room temperature. Whereas the sizes of both αG grains and α′ martensite constituents increased with increasing the first annealing time, both the volume fraction and the chemical concentration of each phase were insignificantly changed. When the first-annealed specimens were annealed again at 640 °C for 5 min, the specimens exhibited bimodal-grained structures with coarse αG and ultrafine lath-shaped ferrite (αL) and retained austenite (γL). The coarse αG came from αG pre-existing in the first-annealed specimen; the fine αL and γL formed by the α′ martensite to γ diffusive reverse transformation. The second-annealed specimens exhibited a transition of yielding behavior from discontinuous yielding with yield-point elongation (YEL) to continuous yielding without YEL due to the coarsening of αG grains with increasing the first annealing time up to 22 h.

AB - The objectives of the present study were to develop the bimodal-grained microstructure in a medium Mn steel without the addition of Al only through a thermo-mechanical process, and to systematically investigate the relationship between the bimodal-grained microstructure and yielding behavior. The cold-rolled Fe-7Mn-0.05C (wt.%) steel with deformed α′ martensite was annealed twice with different temperatures and holding times. When the cold-rolled specimens were first-annealed at 660 °C for 4 h-22 h, the specimens showed a dual-phase microstructure consisting of globular-shaped ferrite (αG) and thermally induced α′ martensite at room temperature. Whereas the sizes of both αG grains and α′ martensite constituents increased with increasing the first annealing time, both the volume fraction and the chemical concentration of each phase were insignificantly changed. When the first-annealed specimens were annealed again at 640 °C for 5 min, the specimens exhibited bimodal-grained structures with coarse αG and ultrafine lath-shaped ferrite (αL) and retained austenite (γL). The coarse αG came from αG pre-existing in the first-annealed specimen; the fine αL and γL formed by the α′ martensite to γ diffusive reverse transformation. The second-annealed specimens exhibited a transition of yielding behavior from discontinuous yielding with yield-point elongation (YEL) to continuous yielding without YEL due to the coarsening of αG grains with increasing the first annealing time up to 22 h.

UR - http://www.scopus.com/inward/record.url?scp=84966430647&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84966430647&partnerID=8YFLogxK

U2 - 10.1016/j.jallcom.2016.04.014

DO - 10.1016/j.jallcom.2016.04.014

M3 - Article

AN - SCOPUS:84966430647

VL - 681

SP - 580

EP - 588

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

ER -