Experimental study of residual stresses of Cam produced by heat treatment and grinding processes

Abstract

The excessive residual stresses caused by heat treatment and grinding processes is one of the main challenges for Cam manufacturing, because they will lead to delayed cracks and reduce the fatigue life of Cam. Experimental studies are one of the essential ways to keep residual stresses at a reasonable value. Thus, orthogonal and single-factor experiments are carried out to explore the effect of heat treatment and grinding processes on the residual stresses of the Cam. The heat treatment processes include quenching temperature, tempering temperature, and tempering holding time. The grinding process includes grinding speed and feed speed. Besides, the superimposed residual stresses produced by heat treatment and grinding processes are analyzed. The results show that the heat treatment and grinding processes produce compressive residual stresses. The heat treatment process combined with the grinding process increases the superimposed residual stress. In addition, the critical factor for the distribution of the final stresses on the Cam surface is the grinding process, and the grinding speed plays the most important role. Therefore, in order to optimize the Cam machining processes to control the residual stresses, the optimization sequence is grinding speed, quenching power, and tempering temperature. The processes to obtain the least stress are as follows: 128 kW of quenching power, 200 °C of tempering temperature and 8 h of tempering time.