| 摘要 |
A cold rolled steel sheet capable of enhancing yield strength and lowering plastic anisotropy by fine (Mn,Cu)S precipitates and AlN precipitate and a method for manufacturing the same are provided. A cold rolled steel sheet having excellent plastic anisotropy has a composition comprising, by weight percent, 0.005% or less of C, 0.2% or less of Mn, 0.01 to 0.2% of Cu, 0.005 to 0.08% of S, 0.1% or less of Al, exceeding 0.004% to not more than 0.02% of N, 0.2% or less of P, 0.0001 to 0.002% of B, 0.002 to 0.04% of Nb, 0.005 to 0.15% of Ti, and the balance of Fe and other unavoidable impurities, and satisfies relational expressions, Cu+Mn=0.05 to 0.4, 0.003<=S^*<=0.015, 1<=(Mn/55+Cu/63.5)/(S^*/32)<=30, 0.8<=(Ti^*/48+Nb/93)/(C/12)<=5.0, 0.003<=N^*<=0.01, and 1<=(Al/27)/(N^*/14)<=10, wherein S^*=S-0.8Î(Ti-0.8ÎN(48/14))Î(32/48), Ti^*=Ti-0.8ÎS(48/32)-0.8ÎN(48/14), N^*=N-0.8Î(Ti-0.8ÎSÎ48/32)Î14/48, and an average size of (Mn,Cu)S precipitates and AlN precipitate is 0.2 mum or less.
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