Author(s): Zhang Xingjin, Wu Huiliang, Chen Yongnan, Zhang Zhaoping
Pages: 35-38
Year: 2015 Issue:  4
Journal: Wide and Heavy Plate
Keyword:  Plastic mould steel; Heat treatment; Microstructure;
Abstract: The paper describes the microstructure observation and hardness determination by using optical micro-scope,scanning electron microscope and Vickers hardness tester,studies the changing law of microstructure and hard-ness obtained under the conditions of different pre - hardening heat treatment process parameters such as quenching temperature,quenching medium,tempering temperature. The results show that lath martensite and bainite in the micro-structure of water quenched and air quenched steel gradually decrease with the increase of tempering temperature,fer-rite gradually increases and grows up,the carbide increases and hardness gradually decreases;the flake type M/ A con-stituent between laths,higher displacement density and fine carbide in ferrite attains a relatively higher hardness as the water quenched steel tempered in 620 ℃,and the process parameters ensuring an optimum prehardening result of the steel grade is determined.