LOW-ALLOY BORON STEEL OF HIGH TREATABILITY Russian patent published in 2009 - IPC C22C38/54 C22C38/32 

FIELD: metallurgy.

SUBSTANCE: invention relates to ferrous metallurgy, particularly to manufacturing of boron steel, used for manufacturing of components in automobile industry, including for manufacturing of components of type toothed wheel of gearboxes, components of undercarriage of tractors and automobiles of heavy payload. Steel is smelted with usage of metallised pellets and contains carbon, manganese, silicon, sulphur, chrome, boron, nickel, molybdenum, aluminium, nitrogen, calcium, oxygen, tin, titanium, iron and unavoidable admixtures, at following ratio wt %: carbon 0.14 - 0.23, manganese 0.90 - 1.40, silicon 0.15 - 0.40, sulphur 0.020 - 0.035, chrome 0.90 - 1.40, nickel 0.15 - 0.35, molybdenum 0.05 - 0.12, aluminium 0.02 - 0.05, nitrogen 0.005 - 0.015, calcium 0.0004 - 0.0050, boron 0.001 - 0.003, oxygen ≤ 0.0025, tin ≤ 0.025, titanium ≤ 0.005, iron and unavoidable admixtures are the rest. Overall content of manganese, chrome, nickel and molybdenum is 2.50 - 3.05. In the capacity of unavoidable admixtures steel contains phosphorus not more than 0.025 wt % and copper not more than 0.15 wt %.

EFFECT: there are increased characteristics of steel hardenability, improved treatability and reduced distortion at thermal treatment, that provides guaranteed level of consumer properties of products.

2 cl