Effect of Austenite Grain Size on Hardenability and Impact Toughness of SCM435H

Abstract

The effects of austenite grain size on hardenability and impact toughness were investigated. The results show that: Since the beginning of the two-phase region with quenching temperature, the austenite grain size from the initial 4+6 mixed crystal at 740°C, and gradually increased to 10 at 860°C; Austenite grain size and hardenability was directly proportional to the austenite grain size increased from 8μm to 36μm, the biggest change is the hardness 10HRC; Austenite grain size and impact toughness is linear, with the decrease of grain size, the impact energy increases linearly, and the austenite grain size and impact toughness curve fitting. Comprehensive analysis for ensuring the hardenability of cold heading steels should be considered optimal matching of material strength and plasticity.