The Use of Navy C-Ring Specimens to Investigate the Effects of Initial Microstructure and Heat Treatment on the Residual Stress, Retained Austenite, and Distortion of Carburized Automotive Steels

Steels such as SAE 8620 and PS-18 are typically used in the carburized condition for powertrain applications in the automotive industry. Such steels always contain retained austenite to varying degrees in both the ashardened and tempered microstructures. As well as retained austenite, heat treatment can produce residual stresses, which lead to both size and shape distortions. The intent of this study was to investigate the effects of initial microstructure, composition, and heat treatment on the amount of residual stress, retained austenite, and distortion in carburized SAE 8620 and PS-18 steels. A specially designed specimen, the Navy C-ring, was used to evaluate distortion. X-ray diffraction techniques were used to determine the residual stress and the amount of retained austenite.