TUBE STOCK OUT OF MICRO ALLOYED MANGANESE CONTAINING STEEL Russian patent published in 2008 - IPC C21D8/10 C22C38/60 C22C38/48 

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy, particularly to production of tube stock with diameter from 80 to 180 mm. To facilitate upgraded level of consumer characteristics, minimal level of anisotropy of mechanical properties, weldability and upgraded resistance of temper brittleness the stock is made out of steel containing, wt %:carbon 0.13-0.18, manganese 1.00-1.40, silicon 0.10-0.30, aluminium 0.015-0.050, vanadium 0.005-0.05, chromium 0.005-0.08, nickel 0.005-0.20, copper 0.005-0.20, molybdenum 0.001-0.08, arsenic 0.0001-0.03, tin 0.0001-0.02, lead 0.0001-0.01, zinc 0.0001-0.005, iron and unavoidable impurities - the rest, at a following ratio: As+Sn+Pb+5×Zn≤0.07, impurities: phosphorus not more, than 0.020%, sulphur not more, than 0.010%, nitrogen not more, than 0.015%. The stock is made hot rolled and normalised, it has ferrite-pearlite structure, the dimension of the actual grain 6-9 points, macrostructure for central porosity, pointed non-uniformity, liquation square, sub-shrinking liquation not more, than 3 points for each kind, liquation strips - not more, than 1 point, non metallic inclusions of pointed sulphides, pointed oxides, stripped oxides, fragile silicates, plastic silicates, non deformed silicates for each kind of not more, than 4.0 points, tensile strength is 450-620 N/mm², yield point is not more, than 310^{N/mm2, specific elongation is not less, than 16%, contraction ratio is not less, than 40%.}

EFFECT: producing tube stock with upgraded level of consumer characteristics.

5 cl, 3 ex