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The application of tailored blanks to autobody parts has progressed because of its numerous advantages. The forming of tailored blanks has, however, a lot of technical problems. Among the problems, weld-line movement and formability deterioration are the most significant ones in case of deep drawing. The weld-line movement and formability change were examined experimentally as a function of weld-line location in square cup deep drawing. The weld-line movement of tailored blank consists of two sources. One is the geometrical reason, and the other is due to the hardening of weld bead. The formability of tailored blank is inferior to that of an original blank by the existence of hardened weld region. The mode of fracture changes from wall breakage to a fracture adjacent to punch radius when the weld-line was close to the punch corner.

A new joining method has been attempted in aluminum hood application to join steel reinforcements to aluminum inner panel. This method, Tox mechanical clinching(TMC), offers the best cost performance and productivity among several joining methods. This paper was focused on the practical understanding of TMC method and its applicability to aluminum hood manufacture. The results of this study showed that design by the TMC could be much easier than that by resistant spot welding(RSW) because TMC produced very reliable and consistent joint strength at the multipoint situation. The only drawback of this method was the low joint strength due to very small joint area. In order to maintain similar joint strength as that of steel hood welded by RSW, the number of TMC points should be increased. Approximately two times of more TMC points produced no problems during durability test of aluminum hood.