Patent ID: 7758707

Claim:
Martensitic stainless steel to be used for making cutting tools, wherein the steel contains 0.40 to 0.55 wt % carbon, 0.8 to 1.5 wt % silicon, 0.7 to 0.85 wt % manganese, 13.0 to 14.0 wt % chromium, 1.0 to 1.5 wt % molybdenum and 0.2 to 0.4 wt % nickel, 0.02 to 0.04 wt % nitrogen, the balance of the steel being iron and inevitable impurities, and wherein the steel, after casting, hot rolling, annealing, cold rolling, hardening and tempering, has a Vickers hardness Hv1 between 700-780.