| 摘要 |
PROBLEM TO BE SOLVED: To provide a high sulfur free-cutting steel in which the formation of coarse sulfides and hard carbosulfides is suppressed while increasing the content of S, in its turn, machinability is extremely satisfactory, and also, deterioration in surface properties caused by the falling of inclusions, the reduction of air-tightness or the like are hardly caused. SOLUTION: The high sulfur free-cutting steel essentially consists of Fe, and comprises, by mass, 0.03 to 0.2% C, 0.4 to 1% S, 0.5 to 3% Mn and≤0.01% O. Then, any of compositional conditions (1) to (3)expressed by the following is sufficed: (1), provided that the content of Ti is defined as WTi (mass%), and the content of oxygen as WO, WTi is, by mass, 0.01 to 0.12%, and also, WTi/WO≥4.5 is satisfied; (2), provided that the content of Al is defined as WAl (mass%), and the content of oxygen as WO, WAl is 0.001 to 0.05%, and also, WTi/WO≥0.05 is satisfied; (3), provided that the content of Zr is defined as WZr (mass%), and the content of oxygen as WO, WZr is 0.001 to 0.05%, and also, WZr/WO≥0.05 is satisfied. Further, the total content of Ti and Zr is≤0.12 mass%. COPYRIGHT: (C)2004,JPO&NCIPI
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