Tools and Technologies for Hot Forming with Local Adjustment of Part Properties
In general hot stamped car body parts show a uniform strength distribution. Especially for safety relevant parts with high requirements concerning crash performance, this uniform strength distribution can cause problems. During a crash a B-pillar e. g. can absorb more energy when the lower part is relatively flexible while the middle and upper part has to be high-tensile to prevent the intrusion into the passenger compartment. Also during the production of hot stamped parts, the high strength causes trouble. When the trimming takes place after the hardening process, the durability of the tool is limited. Thus at the moment the only economic process for trimming of ultra-high-strength steels is laser cutting. This paper presents different approaches to reach local different strength distributions in hot stamped components. In particular the results of a research project of the Institute Tools & Forming, Graz University of Technology are shown where precisely defined areas of different strengths could be obtained in one part. This was achieved by the use of simple and cheap ceramic inserts in conventional press hardening tools.
T. Chandra, N. Wanderka, W. Reimers , M. Ionescu
R. Kolleck and R. Veit, "Tools and Technologies for Hot Forming with Local Adjustment of Part Properties ", Materials Science Forum, Vols. 638-642, pp. 3919-3924, 2010