| 摘要 |
PROBLEM TO BE SOLVED: To provide tool steel excellent in weldability and machinability without deteriorating its mechanical properties such as toughness and wear resistance. SOLUTION: This tool steel has a compsn. contg., by weight, 0.45 to <0.65% C, 0.1 to 2.1% Si, 0.1 to 1.2% Mn, 4.5 to 12.0% Cr, one or two kinds of Mo and W so as to satisfy (Mo+1/2W): 1.5 to 3.5%, 0.05 to <0.5% V, and the balance Fe with inevitable impurities, in which eutectic value Z [=8×(C%)+0.6×(Cr%)] is controlled to <=10.8. Preferably, the content of Cr is controlled to 4.5 to 9.0%, those of one or two kinds of Mo and W are controlled so as to satisfy (Mo+1/2W):1.5 to 2.5%, that of S is controlled to 0.005 to 0.1%, that of Ni is controlled to <=5.0%, and that of Ca is controlled to <=100 ppm. Additionally, it is applied to quenching at 1000 to 1050 deg.C and tempering at >=500 deg.C to control its hardness to <=55 HRC.
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