Optimization of heat treatment process of 980 MPa cold-rolling dual phase steel

doi:10.13251/j.issn.0254-6051.2020.07.018

Abstract

Abstract: Effects of soaking temperature, slow cooling temperature and overaging temperature during continuous annealing on mechanical properties and microstructure of DP980 steel were investigated by means of Gleeble-3500 annealing simulator, optical microscope and tensile testing machine. The results indicate that the martensite content of the DP980 steel is increased with the increase of soaking temperature, which leads to the enhancement of yield strength and tensile strength accordingly. The optimal soaking temperature is 780 ℃. Effect of slow cooling temperature on mechanical properties of DP980 steel is investigated based on the control capability of equipment, and 670 ℃ is selected as the optimal temperature. Besides, the overaging temperature has been possessed large adjustment range on yield strength of DP980 steel, which can reduce the yield ratio significantly. With the increase of overaging temperature, the martensite content is remained stable and a little carbide is precipitated, which reduces the martensite strength and improves the plasticity of DP980 steel. The optimal parameters of soaking temperature, slow cooling temperature and overaging temperature are 780, 670, 320 ℃, respectively.

Key words: DP980 steel, continuous annealing, microstructure, mechanical properties

CLC Number:

TG156.2

Chen Zhuo, Jin Bin, Wang Chengsi, Liu Jingbao, Kuang Shuang, Liu Liping, Wang Zhao, Li Mengxing, Yang Mingwei, Wang Jinrong. Optimization of heat treatment process of 980 MPa cold-rolling dual phase steel[J]. Heat Treatment of Metals, 2020, 45(7): 86-89.

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