| 摘要 |
PURPOSE:To easily obtain a cold rolled steel plate of superior formability for deep drawing by subjecting a hot rolled steel of specific composition to coiling, cold rolling, preheating and holding, recrystallization annealing and cooling treatment respectively in specific conditions then to over aging treatment after reheating. CONSTITUTION:A steel consisting of <=0.10% C, <=0.20% Si, 0.10-0.40% Mn, <=0.03% P, 0.02-0.15% Al, 0.0025-0.20% N and the balance iron and unavoidable impurities is hot rolled and is coiled at >=600 deg.C. After pickling, it is cold rolled at >=40% draft. Thence, it is preheated and held to and at a temp. region above 350 deg.C and below recrystallization temp. for a short time, following which it is held for a short time in a temp. region above the recrystallization temp. and below 800 deg.C, whereby it is again subjected to recrystallization annealing. Further it is lowered of temp. down to a 250-450 deg.C temp. region or is quenched down to below 200 deg.C, and after it is reheated, it is over aged. |
