REFRACTORY MARTENSITIC STEEL Russian patent published in 2012 - IPC C22C38/54 

FIELD: metallurgy.

SUBSTANCE: proposed steel comprises carbon, silicon, manganese, chromium, phosphorus, sulfur, tungsten, copper, nickel, cobalt, nitrogen, tin, niobium, boron, vanadium, titanium and iron in the following ratio, in wt %: carbon - 0.080 - 0.120, silicon - not over 0.100, manganese - 0.050 - 0.100, chromium - 9.500 - 10.000, nickel - not over 0.200, tungsten - 1.800 - 2.200, molybdenum - 0.6 - 0.8, vanadium - 0.180 - 0.250, niobium - 0.040 - 0.070, nitrogen - not over 0.003, boron - 0.008 - 0.01, cobalt - 2.5 - 3.5, sulfur - not over 0.006, phosphorus - not over 0.010, aluminium - not over 0.010, copper not over 0.010, titanium - not over 0010, iron making the rest.

EFFECT: higher strength, heat resistance and impact number.

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