HIGH STRENGTH STEEL SHEET HAVING SUPERIOR FATIGUE CHARACTERISTIC AT SPOT WELDED PART

摘要

PURPOSE:To provide superior fatigue characteristics at a spot welded part to a high strength steel sheet by increasing the amount of Si in the steel sheet and decreasing the amount of P. CONSTITUTION:The composition of a high strength steel sheet is composed of, by weight, 0.3% C, 0.7-1.1% Si, 2% Mn, 0.16% P, 0.02-0.1% acid-sol. Al and the balance Fe with inevitable impurities. In the composition, the amount of P is 0.16% in case of 0.22% C and the amount of P is required to satisfy a formula C+0.6P=0.31% in case of 0.22-0.3% C.