Mechanical properties of laser welded multi material tailor welded blanks

In this study, tailor welded blanks(TWB) were formed between high strength steel(SABC1470) and cold rolled steels(SPFH590 and SPFC980) to improve passenger safety and reduce the weight of cars. Multi material TWB specimens were highly strengthened through the heat treatment of SABC1470. The change in tensile strength caused by the stand by time until water cooling after stamping and the deformation behavior of high speed bending in a statically indeterminate condition such as in the center pillar were evaluated. Multi material TWB specimens that were heat treated at the same temperature tended to show a decrease in tensile and yield strength, depending on the stand by time until water cooling. On the other hand, Multi material TWB specimens(SABC1470+SPFH590) that were heat treated at 850.deg.C showed good properties that were suitable for ensuring passenger safety in car accidents. From the viewpoint of passenger safety, it is best to use SABC1470 and SPFH590 in the upper and lower area of the center pillar, respectively