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

FIELD: metallurgy.

SUBSTANCE: tube stock with diameter from 80 to 180 mm produced out of low carbon low alloyed steel, containing, wt %: carbon 0.43-0.52, manganese 0.90-1.20, silicon 0.17-0.37, 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 following ratio: As+Sn+Pb+5Zn≤0.07, C+Mn/6+Cr/5≤0.72, at that it has laminar ferrite-pearlite structure, dimension of actual grain is 6-9 points, its macrostructure for central porosity, pointed non-uniformity, liquation square, sub-shrinking liquation is not more, than 3 points in each kind, liquation strips not more, than 2 points, non-metallic inclusions - sulphides, pointed oxides, stripped oxides, fragile silicates, plastic silicates, non-deformed silicates - not more, than 4.0 points for each kind of inclusions, tensile strength not less, than 655 H/mm², yield strength not less, than 379-552 H/mm² and specific elongation not less, than 15%. According to invention production of tube stock facilitates optimal ratio of hardness, plasticity and viscosity and minimal level of anisotropy of mechanical properties.

EFFECT: upgraded level of consumer characteristics.

2 cl, 1 ex