Hot Forging Design of Cam for Vessel Engine Using Finite Element Analysis and Ductile Fracture Criteria

The hot forging process of an exhaust cam for a vessel engine was designed by finite element simulation and experimental analysis. An aim of process design was to achieve the near-net shaped cam forgings by hot forging process. From deformation processing map based on the dynamic materials model and instability criterion, the initial heating temperature of the cam material was determined as 1200 degrees C. In order to predict safe processing conditions, the modified Cockcroft-Latham criteria were utilized. Critical damage values varying with process variables of the cam material were generated by analyzing hot tensile tests. The critical damage values, local state of stress, strain, strain rate and temperature were then determined at the point of necking. FE analysis coupling with the modified Cockcroft-Latham criteria model was simulated to predict the formation of forming defects and deformed shape with different forging designs. Optimum process design suggested in this work was made by comparing with the cam for vessel engine manufactured by actual process.