Hot stamping of high strength steel with tailored properties by two methods

摘要

Hot stamped components with foil martensite exhibit ultrahigh tensile strength and hardness, whereas the poor ductility restricts their application on certain components, such as B pillar, which needs multi strength in different regions. It is essential to partly achieve softer structure with high ductility, to enhance the crashworthiness and energy absorption of the whole component and thus improving the safety performance. This work described the hot stamping of high strength steel with tailored properties by two methods, namely applying different die temperatures and annealing processes. The hardness distribution, tensile strength and ductility in different regions of the hot stamped components were gained under the conditions of above two methods to realize the tailored properties. Regardless of the decrease of tensile strength, the total elongation of annealed zone can reaches 20.6% while the heating zone can only obtain its elongation of 10.8%. The results show that annealing hardened part to get tailored properties brings about better performance.