STEEL FOR GAS AND OIL PIPELINES Russian patent published in 2004 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: invention provides alloyed steel for products operated at very low temperatures and exposed to action of corrosive media causing hydrogen-stress cracking. Steel is composed of, wt %: carbon 0.02-0.07, manganese 1.45-1.80, silicon 0.03-0.10, vanadium 0.10-0.12, aluminum 0.03-0.05, sulfur ≤ 0.010, phosphorus ≤ 0.012, nitrogen 0.003-0.005 (calcium + barium + magnesium) 0.07-0.10, iron - the balance. EFFECT: ensured high impact elasticity at very liquid temperatures (-70 C) with high level of mechanical properties and increased corrosion resistance against hydrogen-stress cracking in presence of corrosive media containing hydrogen sulfide. 2 tbl