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 turned tube stock with diameter from 100 to 180 mm designed for production of seamless tubes of various applications. To facilitate upgraded level of consumer characteristics and minimal level of anisotropy of mechanical properties the stock is produced out of steel, containing, wt %: carbon 0.12-0.20, manganese 0.40-0.80, silicon 0.10-0.35, molybdenum 0.25-0.35, nitrogen 0.005-0.010, 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, 0.45≤(C+Mn/6+Mo)≤0.67, as impurities steel contains, wt %: phosphorus not more, than 0.25, sulphur not more, than 0.30, chromium not more, than 0.30, nickel not more, than 0.30, copper not more, than 0.30%. The stock is made hot rolled, is subject to normalisation, has ferrite-pearlite structure, the dimension of the actual grain 5-10 points, macrostructure for central porosity, pointed non-uniformity, liquation square with a medium value for each kind of not more, than 2.0 points, sub-shrinking liquation and 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 2.5 points, tensile strength 450-600 N/mm², yield point is not more, than 285^{N/mm2, specific elongation is not less, than 22%.}

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

2 cl, 1 ex