| 摘要 |
PURPOSE:To obtain a cold rolled killed steel plate which is excellent in press moldability and baking hardenability and also low in ordinary temperature aging property by subjecting Al-killed steel plate to a specific heat treatment after cold rolling. CONSTITUTION:An Al-killed steel plate, containing 0.02 to 0.10% C, 0.1 to 0.7% Mn, 0.02 to 0.07% sol Al, and 0.002 to 0.008% Ni, is subjected to hot rolling and then to cold rolling to form steel plate. After cold rolling, the steel plate is tempered at a temperature between the point A1 and the point A3, and then cooled at a cooling rate of 30 to 200 deg.C/hr from the tempering temperature. The use of the Al-killed steel plate enables one to obtain a steel plate which is lower ordinary temperature aging property from temper rolling to press processing and paining and baking processing than that of low-carbon rimmed steel and also excellent in press moldability and baking hardenability without the addition of expensive elements. |
