1. The importance of friction

The first section describes the different methods of high-speed forming of metallic materials, while the second shows how numerical simulation can be used to map stresses, strains and temperatures on the basis of a behavior law established for a falling mass. In this third section, we look at how this numerical simulation approach can be used to evaluate the coefficient of friction between tools and material . The role of friction in high-speed processing can be positive or negative. When one of the tools is driven, as in rolling, then friction is necessary to engage and drive...