STEEL Russian patent published in 1999 - IPC

FIELD: metallurgy; more particularly manufacture of oil and gas pipelines and other welded structures operating at temperatures from -100 C to +450 C. SUBSTANCE: steel comprises components, wt %: carbon, 0.03-0.11; manganese, 0.90-1.80; silicon, 0.06-0.60; chromium, 0.005-0.30; nickel, 0.005-0.30; vanadium, 0.02- 0.12; niobium, 0.03-0.10; titanium 0.010-0.40; aluminium, 0.010-0.55; 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 and the iron balance. Total content of phosphorus, antimony, arsenic and tin should meet relationship: 2P+Sn+Sb+As is more than 0.035. EFFECT: high viscosity of steel at temperature up to -100 C, embrittlement resistance at temperature up to +450 C, good weldability also in field conditions; products from steel are highly reliable during service life. 2 tbl