| 摘要 |
<p>A non-aging type cold rolled steel sheet capable of enhancing yield strength and lowering in-plane anisotropy by fine MnS precipitates and a method for manufacturing the same are provided. A non-aging type cold rolled steel sheet with high yield ratio comprises, by weight percent, 0.005% or less of C, 0.01 to 0.3% of Mn, 0.005 to 0.08% of S, 0.1% or less of Al, 0.004% or less of N, 0.2% or less of P, 0.0001 to 0.002% of B and 0.005 to 0.15% of Ti with the balance being Fe and other inevitable impurities, wherein the Mn, S, Ti, N and C satisfy relational expressions of 1<=(Mn/55)/(S^*/32)<=30 and 0.8<=(Ti^*/48)/(C/12)<=5.0, wherein S^*=S-0.8Î(Ti-0.8Î(48/14)ÎN)Î(32/48) and Ti^*=Ti-0.8Î((48/14)ÎN+(48/32)ÎS), and wherein MnS precipitates have an average size of 0.2 mum or less.</p> |
