TUBE STOCK OUT OF ALLOYED MANGANESE CONTAINING STEEL Russian patent published in 2008 - IPC C21D8/10 C22C38/14 C22C38/60 

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 at a minimal level of anisotropy of mechanical properties the stock is made out of steel, containing elements, wt %: carbon 0.33-0.41, manganese 1.30 -1.60, silicon 0.40-0.70, vanadium 0.005-0.08, niobium 0.005-0.06, chromium 0.005-0.30, nitrogen 0.005-0.015, 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; [C+Mn/6+(Cr+V+Nb)/5]≤0.71. Impurities are: phosphorus not more, than 0.045%, sulphur not more, than 0.045%, nickel not more, than 0.25%, copper not more, than 0.25%. The tube stock is made continuous cast, hot rolled, thermo refined and turned. The stock has a laminar ferrite-pearlite structure, the dimension of actual grain is 6-9 points, macrostructure is central porosity, pointed non-uniformity, liquation square, sub-shrinking liquation are not more, than 3 points for each kind, liquation strips are not more, than 1 point, non-metallic inclusions: sulphides, pointed oxides, stripped oxides, fragile silicates, plastic silicates, non-deformed silicates - not more, than 4.0 points. Mechanical properties are: tensile strength is not less, than 550 N/mm², yield point is not less, than 430 N/mm², 8 is not less, than 15%, ψ is not less, than 40%.

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

5 cl, 3 ex