PIPE FOR GAS AND OIL PRODUCT LINES AND METHOD OF ITS MANUFACTURE Russian patent published in 2002 - IPC

FIELD: metallurgy, particularly, manufacture of pipes for gas and oil product lines. SUBSTANCE: pipe possesses high process and strength properties, ductility, impact strength at temperatures to minus 100 C, resistance to embrittlement, cracking, corrosion, increased durability and operate reliability. Pipe is manufactured from hot-rolled sheet produced from steel melted from original or pure charge materials with the following amounts of components, wt.%: carbon 0.03-0.11; manganese 0.90-1.80; silicon 0.06-0.60; chromium 0.006-0.30; nickel 0.005-0.30; vanadium 0.02-0.12; niobium 0.03-0.10; titanium 0.010-0.040 aluminum 0.010-0.055; calcium 0.001-0.005; sulfur 0.0005-0.008; phosphorus 0.0005-0.010; nitrogen 0.001-0.012; copper 0.005-0.25; antimony 0.0001-0.005; tin 0.0001-0.007; arsenic 0.0001-0.008; the balance, iron. In this case, content of carbon, nitrogen, copper phosphorus, antimony, tin and arsenic shall satisfies relations: C+10N < 0.14; 10P+Cu < 0.14; 2P+Sn+Sb+As < 0.035, where C, N, P, Cu, Sn, Sb, As are concentration of carbon, nitrogen, phosphorus, copper, tin, antimony and arsenic, wt.%; sheet hot rolling is carried out with reduction degree in each next run reduced by a factor of 1.25-2.5 as compared with that of the previous run. Temperature of rolling shall satisfy the relation in which initial temperature of rolling is lower than finishing temperature of rolling by 200 C. Offered pipe is suitable for operation in aggressive media at temperatures from minus 100 to plus 450 C and under conditions of the Extreme North. Pipes manufactured in compliance with the claimed invention meet all high modern requirements imposed on pipes for gas and oil product lines and kept at the level of the best foreign analogs. EFFECT: high quality product. 2 cl, 4 tbl