C: 0.09%-0.13% Si: 0.10%-0.50% Mn: 0.30%-0.60% P: 0.020% max S: 0.010% max Cr: 8.50%-9.50% Mo: 0.90%-1.10% Nb: 0.06%-0.10% Ni: 0.10%-0.40% N: 0.05%-0.09% Al: 0.040% max V: 0.18%-0.25% W: 0.90%-1.10% B: 0.0005%-0.0050%