In applying high strength steel sheet (HSS) to automotive inner body parts, difficulty occurred in assurance of shape-accuracy, especially side-wall warps, in press forming, because uneven residual stress is apt to become uneven in thickness with an increase in tensile strength. A new press forming method was developed for ensuring shape-accuracy of draw parts with HSS of very high tensile strength such as 780MPa. In the new method, step drawing method was combined with crash forming method by applying cam flange die structure to drawing dies. This method was applied to the "Frame-B, Front" of Tribute etc., which has led to shortening of a stamping-die preparation period. Moreover, with the "Frame-B, Front", application of a 590MPa class HSS was capable of being made for the first time with in-house processing parts, and the thickness of parts was capable of being held down to 1.4mm (it contributes to weight reduction).
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