A Study on the Mechanical Properties and Fatigue Limit of the Austenitizing Treatment Conditions in Austempered Ductile Iron

오스템퍼링처리한 구상흑연주철의 오스테나이트화 조건에 따른 기계적 성질 및 피로한도에 관한 연구

This study was performed to investigate the effect of two step austenitized treatment on the mechanical properties and fracture characteristic of the ductile cast iron and austempered ductile cast iron(ADI). The obtained results of this study were as follows. The matrix structures of specimens were changed differently by austenitizing heat treatment. Microstructure of austempered ductile cast iron obtained by two step austenitized treatment was bainitic ferrite and retained austenite. With two step austenitized treatment, vield strength, tensile strength and hardness decreased, while the elongation increased.