| 摘要 |
PURPOSE:To easily obtain a zinc plated steel plate of improved formability by subjecting a hot rolled steel of specific composition to coiling, cold rolling, preheating and holding, and recrystallization annealing respectively in specific conditions then to over aging treatment at specific temps. after plating. CONSTITUTION:A steel consisting of <=0.10% C, <=0.20% Si, 0.10-0.40% Mn, <=0.30% P, 0.02-0.15% Al, 0.0025-0.25% 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, after which it is held for a short time in a temp. region above the recyrstallization temp. and below 800 deg.C, whereby it is again subjected to recrystallization annealing. Further, it is plated, is lowered of temps. to a 250-450 deg.C temp. region and is over aged or after the plating, it is coiled and is then reheated in a batch furnace, whereby it is overaged at a 250-450 deg.C temp. region. |
