| 摘要 |
Provided is a high-strength bake-hardening cold-rolled steel sheet having superior bake hardening properties, resistance to aging at normal temperature, and deep drawability, as well as low in-plane anisotropy. The sheet contains, by mass, 0.0010-0.0040% carbon, 0.005-0.05% silicon, 0.1-0.8% manganese, 0.01-0.07% phosphorus, 0.001-0.01% sulfur, 0.01-0.08% aluminum, 0.0010-0.0050% nitrogen, 0.002-0.020% niobium, and 0.005-0.050% molybdenum. The [Mn%]/[P%] ratio is 1.6-45, [C%] - (12/93) × [Nb%] is 0.0005-0.0025%, and the balance is iron and unavoidable impurities. Integrated X-ray diffraction intensity ratios X(222), X(110), and X(200) for planes {222}, {110}, and {200} parallel to a plane positioned at 1/4 the depth of the sheet thickness satisfy the equation X(222)/{X(110) + X(200)} ? 3.0. Tensile strength is 300-450 MPa. |
