| 摘要 |
PROBLEM TO BE SOLVED: To provide free-cutting hot tool steel which has satisfactory die workability in pre-hardening. SOLUTION: The free-cutting hot tool steel has a composition containing, by mass, 0.2 to 0.6% C, 0.1 to 1.5% Si, 0.1 to 1.5% Mn, 0.1 to 1.5% Ni, 0.005 to 0.1% S, 2.0 to 8.0% Cr, and 0.0001 to 0.01% Mg, and satisfying 1/2W+Mo: 0.2 to 2.0 and V/Nb/: 0.1 to 1.5, and the balance Fe with inevitable impurities. Alternatively, the free-cutting hot tool steel contains 0.0001 to 0.01% Ca in addition to the composition of the above steel. Alternatively, the free-cutting hot tool steel has a sulfide having mean particle diameter of≤10μm in the above steel. COPYRIGHT: (C)2004,JPO
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