| 摘要 |
PROBLEM TO BE SOLVED: To provide die steel having satisfactory die workability in a prehardend state in which the stabilization of a die life made compatible with workability can be attained by reducing its crack sensitivity. SOLUTION: The prehardend die steel is obtained by subjecting steel comprising, by mass, 0.1 to 0.6% C, 0.1 to 1.5% Si, 0.1 to 0.7% Mn, 1.0 to 6.0% Cr, 0.05 to 1.2% Ni, 0.005 to 0.06% S, 0.5 to 2.5% Mo+1/2W and 0.1 to 2.0% V+1/2Nb, and the balance Fe with inevitable impurities to hot rolling at a forging ratio (s) of 4 to 10 and thereafter subjecting the same to hardening so as to be cooled in such a manner that the cooling rate in the range from the quenching temperature to a temperature lower than that by 500°C is controlled to≥3°C/min. COPYRIGHT: (C)2005,JPO&NCIPI
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