| 摘要 |
<p>A steel sheet satisfactory in coating curability in baking and cold slow-aging property; and a process for producing the steel sheet. The steel sheet contains 0.0005-0.0040 mass% carbon, up to 0.8 mass% silicon, up to 2.2 mass% manganese, 0.0005-0.009 mass% sulfur, 0.4-1.3 mass% chromium, 0.003-0.020 mass% oxygen, 0.045-0.12 mass% phosphorus, 0.0002-0.0010 mass% boron, up to 0.008 mass% aluminum, and 0.001-0.007 mass% nitrogen, with the remainder consisting of iron and unavoidable impurities. Nitrogen in a solid solution state is caused to remain in an extra-low-carbon steel, and chromium, phosphorus, boron, and oxygen are added thereto. Thus, a hot-rolled and cold-rolled steel sheet and a cold-rolled steel sheet plated with zinc by hot dipping can be obtained which each combines high coating curability in baking with cold slow-aging property.</p> |
