| 摘要 |
<p>The invention provides a cold-rolled steel sheet excellent in paint bake hardenability and ordinary-temperature non-aging property comprising, in mass%, C: 0.0005 - 0.0040%, Si: 0.8% or less, Mn: 2.2% or less, S: 0.0005 - 0.009%, Cr: 0.4 - 1.3%, O: 0.003 - 0.020%, P: 0.045 - 0.12%, B: 0.0002 -0.0010%, Al: 0.008% or less, N: 0.001 - 0.007%, and a balance of Fe and unavoidable impurities. Ultra-low-carbon steel retaining solute N and containing added Cr, P, B and O is used to produce hot-rolled and cold-rolled steel sheet and hot-dip galvanized cold-rolled steel sheet that exhibit both high paint bake hardenability and ordinary-temperature non-aging property.</p> |
