| 摘要 |
PURPOSE: Provided is a method for manufacturing p-contained super low carbon steel sheets having superior deep drawing property where a large quantity of Ti is added to P-contained super low carbon steel and sequential step-cooling processes are adopted to improve deep drawing property. CONSTITUTION: The P-contained super low carbon steel sheet is manufactured by hot rolling a steel slab comprising C 0.005wt.% or less, Si 0.02wt.% or less, Mn 1.0wt.% or less, P 0.02-0.10wt.%, S 0.005wt.% or less, N 0.002wt.% or less, sol-Al 0.01-0.04wt.%, Ti 0.05-0.15wt.%, Nb 0.05wt.% or less, 6.5Nwt.%+3Swt.%=<Zr=<0.03wt.%, a balance of Fe, and other inevitable impurities at over 910deg.C; rapid-cooling the hot rolled steel sheet to 680-720deg.C at a cooling rate of 30-70deg.C/sec; air-cooling the steel sheet to 630-650deg.C for 5-10sec, followed by rapid cooling; coiling it in the temperature range of 550-600deg.C and then cold rolling; and then continuous annealing the cold rolled steel sheet at a temperature of 780 to 850deg.C followed by cooling.
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