| 摘要 |
PROBLEM TO BE SOLVED: To provide a high strength cold rolled steel sheet for deep drawing, excellent in surface characteristic, while increasing strength by the addition of P and preventing the occurrence of surface ruggednss after press working. SOLUTION: This steel sheet has a composition consisting of, by weight, <=0.08% C, <=1.0% Si, 0.1-2.5% Mn, 0.04-0.15% P, <=0.02% S, 0.01-0.1% sol.Al. <=0.01% N, and the balance Fe with inevitable impurities or further containing one or >=2 kinds among 0.005-0.1% Ti, 0.005-0.1% Nb, 0.005-0.1% V, 0.01-2% Cr, and <=0.005% B. Further, when the degree of segregation of P in one part is represented by (α) and [α=(concentration of P in the part)/(average concentration of P in the steel)] is satisfied, the value of the ratio between the maximum valueαMAX and minimum valueαMIN of the degree of segregation in the cross section of the steel sheet,αMAX/αMIN, is regulated to <=4.
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