Estimation of die service life against plastic deformation and wear during hot forging processes

This paper describes the estimation method of die service life based on wear and the plastic deformation of dies in hot forging processes. Die service life is considerably shortened due to the thermal softening of surface layer, caused by the high thermal load and long contact time between the dies and the deforming material. Also, the die service life depended on wear and the plastic deformation of dies can be to a large extent determined by finite element (FE) analysis, wear and thermal softening tests. These are some of the major limiting factors affects die accuracy and die service life, and forming velocity and initial die temperatures influence greatly wear and the plastic deformation of hot forging dies. In this study, two methods are suggested for estimating the service life of hot forging dies by plastic deformation and abrasive wear, and these applied to predict the product quantity according to two main process variables, forming velocity and initial die temperature for a spindle component. Through the applications of the suggested methods, the thermal softening of dies due to the local temperature rise led to the reduction of the service life of hot forging dies by plastic deformation more than by abrasive wear.