PIPE MADE OF MARTENSITE STAINLESS STEEL FOR OIL WELLS Russian patent published in 2009 - IPC F16L9/02 C21D8/10 C22C38/58 C22C38/38 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy field, particularly to manufacturing of pipe from martensite stainless steel for usage in humid condition, containing gaseous carbon dioxide. Oil-and-gas pipe is manufactured from steel, containing in wt %: carbon from 0.005 up to 0.1, silicon from 0.05 up to 1, manganese from 1.5 up to 5, phosphorus maximum 0.05, sulphur maximum 0.01, chrome from 9 up to 13, nickel maximum 0.5, molybdenum maximum 2, copper maximum 2, aluminium from 0.001 up to 0.1, nitrogen from 0.001 up to 0.1, iron and unavoidable admixtures are the rest. Pipe allows variety of deplated by chrome section sunder surface without implementation of tempering operation.

EFFECT: it is provided deceleration of corrosion cracking process under tension without formation on surface of passivating film.

3 cl, 2 tbl, 1 ex