Investigation of deformation behaviour with yield point phenomenon in cold-rolled medium-Mn steel under hot stamping conditions
File(s)
Author(s)
Type
Journal Article
Abstract
Medium manganese (MMn) steels are a promising class of advanced high-strength steels (AHSS) with potential for application as vehicle panels in the automotive industry. In this study, the deformation behaviour of a representative cold-rolled MMn steel and its dependence on processing parameters are studied using uniaxial tensile testing under low-temperature hot stamping (LTHS) conditions, covering austenitisation soaking times of 60–600 s, deformation temperatures of 500–700 °C and strain rates of 0.01–5 s−1. A yield point phenomenon is observed for the first time in the early stage of deformation at such temperatures in this MMn steel, which has a submicron grain size. The extent of the yield point phenomenon is reduced, and strain hardening capability and total elongation are enhanced, with longer austenitisation soaking times, which give coarser-grained microstructures. The yield point phenomenon also tends to be weaker at higher deformation temperatures and lower strain rates; under these conditions, both the flow stress and the degree of strain hardening decrease, while the total elongation is insensitive to differences in deformation conditions. The mechanisms for the deformation behaviour and its dependence on test conditions are discussed. In addition, a set of unified constitutive equations is established and calibrated using the experimental data to predict the deformation behaviour of the MMn steel under uniaxial LTHS conditions, and close agreement with experiment, including the yield point phenomenon, is obtained.
Date Issued
2022-08
Date Acceptance
2022-05-02
Citation
Journal of Materials Processing Technology, 2022, 306, pp.1-15
ISSN
0924-0136
Publisher
Elsevier BV
Start Page
1
End Page
15
Journal / Book Title
Journal of Materials Processing Technology
Volume
306
Copyright Statement
© 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Sponsor
ShouGang Research Institute of Technology
Identifier
https://www.sciencedirect.com/science/article/pii/S0924013622001352?via%3Dihub
Grant Number
911101077693981851
Subjects
0910 Manufacturing Engineering
0912 Materials Engineering
0913 Mechanical Engineering
Materials
Publication Status
Published
Article Number
117623
Date Publish Online
2022-05-05