C: 0.08%-0.16% Si: 1.00% max Mn: 2.00% max P: 0.035% max S: 0.015% max Cr: 20.0%-22.5% Mo: 2.50%-3.50% Nb: 0.75%-1.25% Ni: 19.0%-21.0% W: 2.00%-3.00% Co: 18.5%-21.0% N: 0.10%-0.20%