| 摘要 |
<p>The invention relates to high strength cold rolled steel sheet and high strength zinc-coated steel plate sheet mainly used as structural components and reinforcing members of a vehicle body, these steel sheets include remarkable formability and coating property and comprise: 0.01-0.2 weight percent of carbon (C), 0.01-2 weight percent of silicon (Si), 0.5-4.0 weight percent of manganese (Mn), less than 0.1 weight percent of phosphor (P), less than 0.03 weight percent of sulfur (S), less than 1.0 weight percent of soluble aluminum (Sol.Al), 0.001-0.1 weight percent of nitrogen (N), 0.005-1.0 weight percent of stibium (Sb), and remaining ferrum (FE) and inevitable impurities. The invention also relates to the zinc-coated steel plate sheet and a manufacturing method for these steel sheets. In accordance with the invention, remarkable coating property can be attained and tensile strength is more than 490 MPa. In the other hand, the formability thereof is ensured, TS*El balance thereof is more than 15,000. Furthermore, the outstanding bake hardenability of which BH value is more than 80 MPa can be attained.</p> |
