Numerical Simulation and Optimization of Cooling Ducts Layout in Hot Stamping Die

Abstract. As an innovative process of manufacturing ultra high strength steel (UHSS), hot stamping or press hardening is a multi-physical coupling process with complex changes in thermal, mechanical and phase transformation. In this work, in order to study heat transfer from workpiece to upper & lower die and cooling water, a new approach, named Bulk Flow, is adopted to model the cooling ducts and to simulate heat transfer in hot stamping die. Not only can tool design, cooling duct layout and process parameters be studied and optimized to increase the cooling rate and to homogenize temperature distribution in workpiece, but also, the precision of hot stamping simulation be improved. The experimental results of boron steel components formed by the designed die show that the martensite is homogenous. It indicates the feasibility of the bulk flow method．