| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel for a metal mold in which excellent machinability is achieved and small-sized hole workability is improved, and to provide a method for producing the same. SOLUTION: The steel for the metal mold has a composition composed of, by mass, 0.1 to 0.25% C,≤1.0% Si,≤2.0% Mn, 0.6 to 1.5% Ni, >1.0 to 2.5% Cr, Mo and W alone or in combination by≤1.0% in terms of Mo+1/2W, 0.03 to 0.15% V, 0.3 to 2.0% Cu and≤0.05% S, and in which the content of Al is regulated to≤0.l%, the content of N is regulated to≤0.06% and the content of O is regulated to≤0.005%, and the balance Fe with inevitable impurities, and in which a value by formula 1 is≥150: formula 1: 59.9×(Rockwell hardness [HRC])+12,666.8×(the content [mass%] of sulfur)+7.58×(the amount [area%] of lower bainite occupying in the cross-sectional structure)+11.4×(the average crystal grain size [grain size number] of old austenite according to ASTM-E112)+1,531.1. There is provided the method for producing the steel. COPYRIGHT: (C)2011,JPO&INPIT |
