Patent ID: 8057737

Claim:
A forging steel consisting of C: 0.2-1.0% Si: 0.05-0.6%; Mn: 0.2-1.5%; Ni: 4% or below (but not including 0%); Cr: 0.5-4%; Mo: 0.1-1.5%; and V: 0.005-0.3% respectively, while the remainder is Fe and the inevitable impurities, wherein the forging steel has a dissolved Mg concentration is from 0.05 to 5 ppm and a dissolved Al concentration from 50 to 500 ppm; and oxide inclusions having an average composition satisfying the following formulas (1) and (2): [MgO]+[Al 2 O 3 ]â‰§40%â€ƒâ€ƒ(1) [MgO]â‰§5%â€ƒâ€ƒ(2) provided [MgO] and [Al 2 O 3 ] respectively denote the mass amounts in percent of MgO and Al 2 O 3 .