TUBE STOCK OUT OF LOW CARBON MOLYBDENUM CONTAINING STEEL Russian patent published in 2008 - IPC C21D8/10 C22C38/60 

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy, particularly to production of tube stock with diameter from 90 to 180 mm designed for fabricating of seamless tubes of various applications. To facilitate upgraded level of consumer characteristics the tube stock is made out of steel, containing wt %: C (0.08-0.018), Mn (0.40-0.70), Si (0.10-0.50), Cr (0.70-2.5), Mo (0.45-1.20), As (0.0001-0.03), Sn (0.0001-0.02), Pb (0.0001-0.01), Zn (0.0001-0.005), iron and unavoidable impurities - the rest, at the ratio (As+Sn+Pb+5×Zn)≤0.07, as impurities steel contains, wt %: P- not more, than 0.035, S not more, than 0.035, Ni not more, than 0.30, Cu not more, than 0.30. The tube stock is made by means of continuous casting, hot rolled, normalised, it has ferrite-pearlite structure, the dimension of the actual grain is 5-10 points, macrostructure for central porosity, pointed non-uniformity, liquation square is not more, than 2.0 points, sub-shrinking liquation and liquation strips are not more, than 1 point, non metallic inclusions of pointed sulphides, pointed oxides, stripped oxides, fragile silicates, plastic silicates, non deformed silicates are not more, than 2.5 points for each kind of inclusions, tensile strength is 440-650N/mm², yield point is not more, than 305^{N/mm2, specific elongation is not less, than 20%, hardenability with a cut-off diameter is not less, than 35 mm.}

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

5 cl, 3 ex