深絞り加工の薄肉化技術に関する研究

ストレッチドロー法における板厚精度と板材異方性の関係

抄録

A steel sheet for stretch draw forming uses with an ultra thin gauge for high-strength, temper-grade DR9 which usually has larger planar anisotropy. It is the purpose of this paper to clarify the effects of the thickness accuracy of walls obtained by stretch draw forming on the anisotropy of mechanical properties of a steel sheet. This is achieved by the controlling the coiling temperature during the hot rolling process. Experimental results indicate that sufficiently good earing rate property of the steel is obtained by controlling the coiling temperature to be high. The wall thickness of a cup redrawn by the stretch draw method was uniform and thin at center portion. On the other hand, the amount of deviation of the circumferential thickness on redrawn cup wall is increased at the upper portion, and this amount of deviation is related to the anisotropy of steel sheet.