Microstructure and Mechanical Properties of a Cold-Rolled Ultrafine-Grained Dual-Phase Steel

Zhiyi Pan; Bo Gao; Qingquan Lai; Xuefei Chen; Yang Cao; Manping Liu; Hao Zhou

doi:10.3390/ma11081399

Microstructure and Mechanical Properties of a Cold-Rolled Ultrafine-Grained Dual-Phase Steel

Materials (Basel). 2018 Aug 10;11(8):1399. doi: 10.3390/ma11081399.

Authors

Zhiyi Pan¹, Bo Gao², Qingquan Lai^{3

4}, Xuefei Chen^{5

6}, Yang Cao⁷, Manping Liu⁸, Hao Zhou⁹

Affiliations

¹ Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. zhiyipan0602@163.com.
² Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. gaobo@njust.edu.cn.
³ Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094, China. lai@njust.edu.cn.
⁴ State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200444, China. lai@njust.edu.cn.
⁵ State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China. chenxuefei@lnm.imech.ac.cn.
⁶ School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China. chenxuefei@lnm.imech.ac.cn.
⁷ Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. y.cao@njust.edu.cn.
⁸ School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, China. manpingliu@ujs.edu.cn.
⁹ Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. hzhou511@njust.edu.cn.

Abstract

A new processing route to produce Ultrafine-Grained Dual-Phase steel has been proposed, involving cold-rolling and subsequent intercritical annealing of a fibrous ferrite⁻martensite starting structure. Ultrafine-grained DP (UFG-DP) steel with an average ferrite grain size of about ~2.7 μm and an average martensite island size of ~2.9 μm was achieved. Tensile testing revealed superior mechanical properties (the ultimate tensile strength of 1267 MPa and uniform elongation of 8.2%) for the new DP steel in comparison with the fibrous DP steels. The superior mechanical properties are attributed to the influence of microstructure refinement on the work-hardening and fracture behavior.

Keywords: cold-rolling; dual phase steel; intercritical annealing; microstructure refinement.