Tribology Investigation on Aluminum Sheets for Forming Applications

Due to environmental regulations the automotive industry is nowadays forced to consider weight reduction of the products. For this reason, lightweight blanks of aluminum alloys are increasingly used. Since the forming behavior of aluminum blanks is different to traditional steel blanks, precise finite element (FE) simulation models of the forming processes are required. Reliable simulations require a coefficient of friction (CoF) which represents actual friction conditions in the forming processes. In this work, the CoF is experimentally investigated using a pin-on-plate tribometer. The tribological tests were performed at different contact pressures using aluminum alloy plates and steel pins. The topography of the plate surfaces before and after the tribology tests were observed using an optical 3D surface profiler. Remarkable plastic deformation of the surface asperities influencing the CoF was observed. The obtained values of the CoF were used for modeling and simulating deep drawing processes with the FE software AutoForm R8. A cross tool geometry was utilized in both the deep drawing simulation and the deep drawing experiment conducted for validating the simulations. Using the measured CoF in the FE model ensures good agreement between the deep drawing simulation and the experiments

Keywords:

Coefficient of friction , Deep drawing , Surface topography , Roughness , Finite element simulations