KNIFE FOR METAL CUTTING Russian patent published in 2011 - IPC C22C38/46 

FIELD: metallurgy.

SUBSTANCE: invention refers to production of steel for knives used in metal-shearing machines operating in wide range of temperatures with lower limit not less, than -30°C in winter time under conditions of wear combined with high impact loads. The knife is made out of steel containing carbon, silicon, manganese, molybdenum, vanadium, nickel, chromium, sulphur, phosphorus and iron at the following ratio of components, wt %: carbon 0.50 - 0.60, silicon 0.10 - 0.40, manganese 0.40 - 0.70, molybdenum 0.60 - 0.80, vanadium 0.30 - 0.60, nickel 1.70 - 2.00, chromium 1.00 - 1.30, sulphur not more, than 0.005, phosphorus not more, than 0.01, iron - the rest. Upon quenching from temperature 920°C and successive tempering at temperature 450±10°C steel has uniform structure wherein a grain has size 5-8 points, impact elasticity 39 J/cm² and hardness 51 HRC.

EFFECT: upgraded hardenability, mechanical property and wear resistance.