| 摘要 |
PROBLEM TO BE SOLVED: To produce steel for a cold die which has excellent machinability more than that of the conventional one while securing the properties to be required such as toughness. SOLUTION: The steel for the cold die has a composition containing, by weight, 0.6 to 2.0% C, 0.1 to 1.2% Si, 0.1 to 1.0% Mn, 0.005 to 0.15% S, 6.5 to 15.0% Cr, 1.0 to 5.0% Mo and W individually or in combination in terms of 2Mo+W, 0.05 to 1.0% V, 0.001 to 0.02% Al, 0.0005 to 0.02% Ca, 0.0005 to 0.01% O and <=0.04% N, and the balance substantially Fe. In the steel, the occupancy ratio of sulfide inclusions containing >=1.0% Ca and present in contact with oxide inclusions containing 8 to 62% CaO is >=2.0×10<-4> mm<2> per the field area of 3.5 mm<2> .
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