Press hardening of alternative materials: conventional high- strength steels

Abstract

The increase in strength of new high strength steels (HHS) and advanced high strength steels (AHHS) has led to forming issues, such as high springback, low formability, increase of forming forces and tool wear. These problems increase thecosts of manufacturing and maintaining stamping tools in the automotive industry. The aim of this research was to analyse the advantages of applying the press- hardening process toconventional HSS and AHSS steel to increase their formability and therefore reduce the number of forming steps and productioncosts. With this aim in mind, the press-hardening process was used to manufacture an industrialcomponent using four different automotive steel grades: dual phase (DP),complex phase (CP), transformation- induced plasticity (TRIP) and martensitic (MS) grade. Springback measurements werecarried out, together with an analysis of the obtained final mechanical properties and microstructures. The results showed that the formability of all the materials increased. The mechanical properties of theCP800 and TRIP700 materials were maintained or even improved, whereas those of the MS1200 and HCT980X materials were significantly reduced. Weconclude that press hardening is a suitable manufacturing process forCP800 and TRIP700components.