| 摘要 |
<p>A cold rolled steel sheet capable of enhancing yield ratio and lowering in-plane anisotropy by AlN precipitates in bake-hardening type interstitial free steel and a method for manufacturing the same are provided. A bake-hardening type cold rolled steel sheet with high yield ratio comprises, by weight percent, 0.001 to 0.01% of C, 0.08% or less of S, 0.1% or less of Al, 0.004 to 0.02% of N, 0.2% or less of P, 0.0001 to 0.002% of B and 0.001 to 0.05% of Nb with the balance being Fe and other inevitable impurities, wherein the Al, N, C and Nb satisfy (Al/27)/(N/14)=1 to 20, and Cs(solid carbon) satisfies 5 to 30, wherein Cs=(C-NbÎ12/93)Î10000, and wherein AlN precipitates have an average size of 0.2 mum or less.</p> |
