STAINLESS STEEL FOR OIL WELL, PIPE FROM SAID STEEL AND METHOD OF MAKING STAINLESS STEEL FOR OIL WELL Russian patent published in 2013 - IPC C22C38/44 C21D8/02 C21D8/10 

FIELD: metallurgy.

SUBSTANCE: stainless steel for oil well comprises the following elements in wt %: C not over 0.05, Si not over 0.5, Mn from 0.01 to 0.5, P not over 0.04, S not over 0.01, Cr over 16.0 and not over 18.0, Ni over 4.0 and not over 5.6, Mo from 1.6 to 4.0, Cu from 1.5 to 3.0, Al from 0.001 to 0.10, and N not over 0,050, Fe and impurities making the rest. Steel microstructure comprises martensite and ferrite phases with volume ratio varying from 10 to 40%. Ferrite phase distribution factor exceeds 85%.

EFFECT: higher strength and rust resistance.

7 cl, 4 dwg, 2 tbl, 44 ex