Cold forged parts are typically subjected to heat treatment to improve their mechanical properties. However, it is desirable to eliminate the heat treatment process to reduce their manufacturing cost. In this study, a strength prediction method using a Chaboche combined hardening model was investigated for predicting the strength of cold forged parts that are not subjected to heat treatment after cold forging, especially those which are subjected to tensile loads during operation in the opposite direction of compressive loads during cold forging. Simple shear tests were performed to obtain stress-strain curves with reversed loading over a wide range of strains. Carbon steels were used as test materials. Simple shear tests assisted in identifying the material parameters of the Chaboche combined hardening model so as to reproduce the stress-strain behavior over a range of strains where cold forged parts are subjected to reversed loads during operation: this facilitated the accurate prediction of the strength of the cold forged parts.
