Numerical-experimental study of a tailored press-hardening technology with intermediate pre-cooling to manufacture an automotive component in advanced high strength steel

Abstract

Abstract. The development of new vehicles generations lighter and safer is still a challenge. Therefore, several companies are looking for innovative and efficient solutions able to combine hard and soft zones in the same structural part. In this work, attention is paid on the press hardening process with the integration of an intermediate pre-cooling, which involves a secondary furnace where the temperature for hard zones is maintained at the complete austenitization one and soft zones are cooled. A numerical-experimental analysis was carried-out to understand how process parameters, i.e., the pre-cooling temperature and the time taken for the pre-cooling phase, influenced the mechanical properties of the component. As a case study, an automotive B-Pillar in USIBOR®1500 was chosen. For this study, a Finite Element (FE) model was developed for the numerical simulation of the press-hardening technology, varying process parameters. The FE thermal cycles were experimentally reproduced on samples using a Gleeble®3180 thermo-mechanical physical simulator. After physical simulation, tensile tests, hardness tests and metallographic analysis were carried out on treated samples, with the aim of measuring their mechanical properties.