| 摘要 |
<p>Provided is a high-strength cold rolled steel sheet and a high-strength zinc-coated steel sheet, which are primarily used as a structural member and a reinforcement of the car body, and has excellent formability and coating properties; and methods for manufacturing the same. The steel sheet comprises 0.01-0.2 wt% of carbon (C), 0.01-2.0 wt% of silicon (Si), 0.5-4.0 wt% of manganese (Mn), less than 0.1 wt% of phosphorous (P), less than 0.03 wt% of sulfur (S), less than 1.0 wt% of soluble aluminum (Sol. Al), 0.001-0.1 wt% of nitrogen (N), 0.005-1.0 wt% of antimony (Sb), and the balance of iron (Fe) with inevitable impurities. Provided is also a zinc- coated steel sheet and preparation thereof using the same steel sheet. According to the present invention, excellent coating properties and high tensile strength of more than 490 MPa can be achieved. In addition, the formability of TS * El balance having 15,000 MPaD % or higher can be secured. Further, excellent bake hardenability of a BH value having 80 MPa or higher can be obtained.</p> |
