COLD ROLLED STEEL SHEET HAVING EXCELLENT CURING PERFORMANCE FOR BAKED PAINT AND COLD DELAYED AGING PROPERTY AND PRODUCTION METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a steel sheet having satisfactory curing performance for baked paint and cold delayed aging properties, and to provide a production method therefor.;SOLUTION: The steel sheet comprises 0.0005 to 0.0040% C, ≤0.8% Si, ≤2.2% Mn, 0.0005 to 0.009% S, 0.4 to 1.3% Cr, 0.003 to 0.020% O, 0.045 to 0.12% P, 0.0002 to 0.0010% B, ≤0.008% Al and 0.001 to 0.007% N, and the balance Fe with inevitable impurities. A hot rolled and cold rolled steel sheet, and, further, a hot dip galvanized cold rolled steel sheet combining high curing performance for baked paint and cold delayed aging properties can be obtained by leaving solid solution N in extra-low carbon steel and adding Cr, P, B and O thereto.;COPYRIGHT: (C)2006,JPO&NCIPI