High strength steel for dies with excellent machinability

Abstract

A high strength steel for dies has excellent machinability and including, by weight, 0.005 to 0.1% C, not more than 1.5% Si, not more than 2.0% Mn, from 3.0 to less than 8.0% Cr, not more than 4.0% Ni, 0.1 to 2.0% Al, not more than 3.5% Cu, and balance of Fe and unavoidable impurities including N and O, and which has a metal structure whose primary microstructure is martensite, wherein N and O as impurities are restricted to amount ranges of not more than 0.02% N and not more than 0.003% O. In the invention, an improvement in the machinability in heavy cutting an improvement in the precision electro discharge machining property and high-grade polishing property can be achieved when the above high strength steel has a chemical composition in which the value of (7.7×C (wt %))+(2.2×Si (wt %))+271.2×S (wt %)) is preferably not less than 2.5 and more preferably not more than 6.