| 摘要 |
A continuous-cast low-carbon resulfurized free-cutting steel which consists in weight percentage of C: 0.05-0.15, Mn: 0.5-1.5, P: 0.05-0.10, S: 0.15-0.40, O: 0.010-0.020, one or more of Pb, Bi, and Te as accompanying elements for improving machinability at a following content: Pb: 0.05-0.40, Bi: 0.05-0.40, and Te: 0.003-0.10, Si: 0.003 or less, Al; 0.0009 or less, and the remainder consisting of Fe and unavoidable impurities, and contains a manganese sulfide-base inclusion with the provision that: a mean sectional area of the manganese sulfide-base inclusion present in a sectional area of 1 mm2 in the rolling direction of the steel is not less than 30 mu m2; and a rate of the number of a manganese sulfide-base inclusions not in the form of a complex with oxide is not less than 80% of the total amount of manganese sulfide-base inclusion. |
