TUBE STOCK OUT OF LOW CARBON STEEL Russian patent published in 2008 - IPC C21D8/10 C22C38/12 C22C38/42 

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy, particularly to production of tube stock with diameter from 100 to 180 mm. To facilitate upgraded level of consumer characteristics at a minimal level of anisotropy of mechanical properties the tube stock is fabricated out of steel, containing, wt %: carbon 0.06-0.14, manganese 0.35-0.65, silicon 0.17-0.37, titanium 0.01-0.03, aluminium 0.020-0.060, vanadium 0.005-0.02, molybdenum 0.005-0.15, niobium 0.005-0.02, nitrogen 0.005-0.005, iron and unavoidable impurities - the rest, as impurities steel contains wt. %: chromium not more, than 0.25, nickel not more, than 0.30, copper not more, than 0.25, sulphur not more, than 0.013, phosphorus not more, than 0.18, at that steel has ferrite-pearlite structure, the dimension of the actual grain is 5-8 points, its macrostructure for central porosity, pointed non-uniformity, liquation square, subshrinking liquation - not more, than 2 points for each kind, liquation strips - not more, than 1 point, non-metallic inclusions - sulphides, pointed oxides, stripped oxides, fragile silicates, plastic silicates, non-deformed silicates - not more, than 4.5 points for each kind of inclusions, tensile strength is 350-480 N/mm², yield point is 235 N/mm², specific elongation is not less, than 28%, contraction ratio is not less, than 55%.

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

1 cl, 1 ex