University of Oulu

Wu, Y., Uusitalo, J., & DeArdo, A. J. (2021). Investigation of the critical factors controlling sheared edge stretching of ultra-high strength dual-phase steels. Materials Science and Engineering: A, 828, 142070. https://doi.org/10.1016/j.msea.2021.142070

Investigation of the critical factors controlling sheared edge stretching of ultra-high strength dual-phase steels

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Author: Wu, Yingjie1,2; Uusitalo, Juha3; DeArdo, Anthony J.1,3
Organizations: 1Basic Metals Processing Research Institute, Department of Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
2Sichuan University, Pittsburgh Institute (SCUPI), Sichuan University, Chengdu, Sichuan, 61000, China
3Centre for Advanced Steels Research, Materials Engineering Laboratory, Department of Mechanical Engineering, University of Oulu, Oulu, FI-90014, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link: http://urn.fi/urn:nbn:fi-fe2022021418885
Language: English
Published: Elsevier, 2021
Publish Date: 2023-09-16
Description:

Abstract

The present study aimed to explore dual-phase (DP) steels with a good combination of high strength and reasonable global ductility (i.e., total elongation and general stretch formability) and local ductility (i.e., sheared edge ductility or hole expansion ratio). Therefore, a series of ultra-high strength dual-phase steels were designed, melted, rolled, annealed and formed. These steels contained various aluminum additions and vanadium contents and were processed with different coiling temperatures and continuous galvanizing line (CGL) thermal path simulations conducted using a Gleeble 3800 system. The microstructures, tensile properties and hole expansion behaviors of all candidate DP steels were determined and compared. The microstructural and damage evolutions in the process of both hole punching and hole expansion were examined. The results indicated that hole expansion ratios of DP steels could be correlated well with (i) the burnished-to-fracture zone ratios in shear surfaces after hole punching, (ii) the values of reduction in area of tensile specimens after fracturing, and (iii) nanohardness difference between soft ferrite and hard constituents. The micro-voids and micro-cracks introduced by hole punching acted as crack initiation sites, which severely affected the subsequent hole expansion process. Therefore, better sheared edge ductility may benefit from microstructures that retard the crack propagation or void growth and coalescence during hole expansion.

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Series: Materials science & engineering. A, Structural materials: properties, microstructure and processing
ISSN: 0921-5093
ISSN-E: 1873-4936
ISSN-L: 0921-5093
Volume: 828
Article number: 142070
DOI: 10.1016/j.msea.2021.142070
OADOI: https://oadoi.org/10.1016/j.msea.2021.142070
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Subjects:
Copyright information: © 2021 Published by Elsevier B.V. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/.
  https://creativecommons.org/licenses/by-nc-nd/4.0/