Effects of material properties on elastic characteristics of cold forged part

The dimension of cold forged part is larger than that of the die cavity. The difference could be originated from the various features, such as the elastic characteristics of die and workpiece, thermal influences, and machine-elasticity. Among these features, elastic behavior of die and workpiece has been considered as the most important element for the precision cold forging. In the present study, the effect of material properties of both workpiece and die on the dimensional precision of forged part was investigated using FE and experimental analyses. Three materials, such as SCM420H, Cu-OFHC and Al6061 alloy, were used to divide the effect of the elastic modulus and flow stress on the dimension specifically. From the results of FEA, the elastic deformation of die was found to be more dominant than that of workpiece. The die expansion depends on the flow stress of workpiece during a loading stage. On the other hand, the die contraction during unloading was affected by both the flow stress and elastic modulus of workpiece. The elastic modulus of workpiece affects the elastic recovery of forged part after ejecting stage.