| 摘要 |
PURPOSE:To manufacture a hot rolled steel sheet superior in deep drawability, by hot rolling and lubrication rolling a carbon steel contg. a specified quantity of C under a specified condition respectively, then performing the recrystallization treatment. CONSTITUTION:The carbon steel contg. <=0.2wt% C is rolled in temp. range of Ar3+100 deg.C or below and Ar3 or above so that the total reduction ratio is regulated at least >=35%. Next, lubrication rolling is applied in temp. range of Ar3 or below and >=550 deg.C by >=50% total reduction ratio under the condition of >=0.2 friction coefft., then recrystallization treatment is performed. The steel contains usually about <=1.5% Mn, about <=0.5% Si, about >=0.03% P, about <=0.02 S, about <=0.1% Al, about <=0.008% N, etc., and about <=0.3% Ti, about <=0.05% Nb. In this way, the hot rolled steel sheet superior in deep drawability having >=1.0 Lankford value is obtained. |
