| 摘要 |
PURPOSE:To obtain superior formabilitity and spot weldability by subjecting a steel plate contg. prescribed amts. of C, Si, Mn, P, sol. Al and rolled under specific conditions to zinc hot dipping treatment at prescribed temps. CONSTITUTION:A steel contg. 0.002-0.15% C, <=0.6% Si, 0.5-1.6% Mn, <=0.15% P, and 0.01-0.1% sol. Al is produced. The ingot of this steel is hot-rolled at 700- 950 deg.C finish temps. and 200-620 deg.C coiling temps., after which it is cold-rolled at >=40% draft. Next, it is box-annealed at 400 deg.C-A1 transformation point. Thence, this annealed steel plate is heated at 480-900 deg.C, and is immersed in a Zn plating bath of 420-520 deg.C bath temps., after which it is subjected to alloying treatment at 520-640 deg.C for 3sec time. |
