| 摘要 |
PROBLEM TO BE SOLVED: To improve the (r) value, to reduce ridging and to improve the corrosion resistance in the subject steel by allowing it to contain a specified compsn. of C, Si, Mn, Cr, Al, Mg, N, P, S and Ti, and the balance Fe with inevitable impurities, in which the contents of the compositional elements satisfy specified relations as well and furthermore controlling the area occupancy ratio of nonmetallic inclusions including Mg to the value equal to or below a specified one. SOLUTION: This steel contains, by weight, <=0.01% C, <=1.6% Si, <=2.0% Mn, 7 to 30% Cr, 0.005 to 0.5% Al, 0.0003 to 0.05% Mg, <=0.05% N, <=0.05% P, <=0.06% S and 0.01 to 1.0% Ti, and the balance Fe with inevitable impurities. Then, the relations of [S]<=2[C] and [Ti]>=[P]+2[O]+2[N]+[S]+4[C]+[Mg] are satisfied, where the elements in the [ ] denote the weight % of the elements. Moreover, the area occupancy ratio of nonmetallic inclusions including Mg is controlled to <=0.1%.
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