Toughness, excellent for a short time and for a long time of softening resistance was hot work tool steel

摘要

PROBLEM TO BE SOLVED: To provide a hot work tool steel that is excellent in toughness and high-temperature strength for extending life of a die.;SOLUTION: The hot work tool steel excellent in toughness comprises, by mass%, 0.2-0.60% C, 0.10-0.50% Si, 0.5-2.0% Mn and 0.05-0.80% V, further comprises at least one chosen from 0.5-2.5% Ni and 1.0-4.0% Cr in a range satisfying the relation: Ni+Cr3.0% and further comprises at least one chosen from 0.30-2.0% Mo and 0.6-4.0% W (provided that, when both, they are contained in a range satisfying the relation: 1/2W+Mo≤2.0%), provided that the value F (C, Si, Mn, Ni, V, Mo, W)=187C[%]+54Si[%]+37Mn[%]+4Ni[%]-Cr[%]-27(Mo+1/2W)[%]+169V[%] satisfies the relation: F≤171, and the balance being Fe and unavoidable impurities.;COPYRIGHT: (C)2012,JPO&INPIT