Influence of the tool temperature increment on the coefficient of friction behavior on the deep drawing process of HSS

Abstract

The use of High Strength Steels (HSS) in the deep drawing processes has an impact on the temperature that is achieved on the die surfaces. Due to the heat that is created through the deformation of the material and the friction itself, the tools temperature increase considerably up to approximately 100°C. This temperature increment has an effect on both the wear of the surface and also the coefficient of friction (COF). In this work the influence of the tool temperature on the coefficient of friction is studied. For that, Strip Drawing Tests have been carried out at different tool temperatures with a DP780, High Strength Steel. Moreover, different contact pressures have been considered in the study to analyse the combined effect of the contact pressure with the temperature increment. It has been proved that the temperature increment has to be taken into account to predict accurately the behavior of the coefficient of friction between the sheet and the tool. This change in the coefficient of friction has a high impact on the prediction of the deep drawing process.