HIGH STRENGTH CORROSION RESISTANT ALLOY FOR OIL INDUSTRY Russian patent published in 2011 - IPC C22C38/50 C22C19/05 C22C30/00 

FIELD: metallurgy.

SUBSTANCE: there is melted alloy containing wt %: 35 - 55% of Ni, 12 - 25% of Cr, 0.5 - 5% of Mo, up to 3% of Cu, 2.1 - 4.5% of Nb, 0.5 - 3% of Ti, up to 0.7% of AI, 0.005 - 0.04% of C, the rest - Fe, random impurities and deoxidisers. Composition of alloy meets the ratio (Nb-7.75C)/(Al+Ti) = 0.5 ÷ 9. Alloy is annealed and is subjected to at least one dispersion hardening to obtain micro-structure containing mixture of phases γ' and γ" with total contents from 10 to 30 wt % and minimal contents of γ" 1 wt % and with minimal yield point 120 ksi. Alloy is annealed at temperature from 1750°F (954°C) to 2050°F (1121°C), dispersion hardening is performed preferably in two stages at temperature from 1275°F (691°C) to 1400°F (760°C) and from 1050°F (565°C) to 1250°F (677°C).

EFFECT: high strength, ductility and corrosion resistance.

15 cl, 2 dwg, 7 tbl