STEEL Russian patent published in 2011 - IPC C22C38/26 

FIELD: metallurgy.

SUBSTANCE: steel contains carbon, manganese, silicon, chromium, vanadium, aluminium, niobium, nitrogen, calcium, iron and impurities at following ratio of components, wt %: carbon from over 0.60 to 0.78, manganese 0.75 - 0.85, silicon 0.20 - 0.35, chromium 0.30 - 0.60, vanadium 0.03 - 0.18, aluminium from over 0.005 to 0.025, niobium 0.001 - 0.015, nitrogen from over 0.01 to 0.025, calcium from 0.0005 to less 0.0010, iron and impurities - the rest. As impurities steel contains sulphur - not over 0.030 %, phosphorus not over 0.030 % and copper not over 0.30 %.

EFFECT: raised operational resistance and hardness on surface and in cross section of milling balls.

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