| 摘要 |
PURPOSE:To obtain the titled steel plate with superior deep drawability and shape by hot rolling and cold rolling a steel contg. specified amounts of C, Si, Mn, Al and Ti and having a specified atomic concn. ratio of (available Ti)/(C+ N) and by carrying out continuous annealing including cooling under a specified condition. CONSTITUTION:A steel contg., by weight, 0.003-0.03% C, 0.1-1% Si, 0.3-1.5% Mn, 1-3% Si+2.Mn, 0.1-0.07% Al and 0.02-0.2% Ti and having 0.4-0.8 atomic concn. ratio of (available Ti)/(C+N) is hot rolled and cold rolled. Said available Ti is obtd. by eliminating Ti as oxide and sulfide from total Ti. Continuous annealing is then carried out by heating at the Ac1 transformation point -900 deg.C for 80sec-10min and cooling at >=80 deg.C/sec average cooling rate. |
