Effect of reversed austenite on low temperature impact fracture process of medium Mn steel

doi:10.13251/j.issn.0254-6051.2021.11.023

Abstract

Abstract: Ultra low carbon 7%Mn steel was tempered at different temperatures and the content of reversed austenite in the steel and the impact absorbed energy at -60 ℃ and -100 ℃ were measured, and the microstructure near impact fracture was observed, then the effects of content and stability of reversed austenite on low temperature impact fracture process of the tested steel were discussed. The results show that the effect of reversed austenite on low temperature toughness of the tested steel has pros and cons. It can alleviate the stress concentration at the crack tip and improve the low temperature toughness of the steel through phase transformation. On the other hand, when the stability of reversed austenite is lower, a large amount of reversed austenite can transform to martensite easily under stress, resulting in the reduction of low temperature toughness. The plastic deformation area near the impact fracture is small, which indicates that it is difficult to achieve toughening by a wide range TRIP effect during impact fracture.

Key words: reversed austenite, medium Mn steel, low temperature toughness, fracture mechanism

CLC Number:

TG142.1

Li Jing, Yang Yuehui, Zhang Xiaojuan, Liang Guoli, Yuan Shaoqiang. Effect of reversed austenite on low temperature impact fracture process of medium Mn steel[J]. Heat Treatment of Metals, 2021, 46(11): 147-151.

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