Inco Alloys International, Inc.

Edward Lee Hibner

James R Crum

William L Mankins

Sarwan Kumar Mannan

Jon M Poole

Ralph W Ross, Jr

Rickey Dale Corn

A heat treatment for hot or cold worked 725 corrosion resistant Ni-base alloys to increase the room temperature yield strength of the material to above about 140 ksi (965 MPa). The material is useful for oil patch and gas turbine applications. The process includes annealing the material at about 1825&deg; F. (996&deg; C.) for about 1.5-4 hours, age hardening the material at about 1400&deg; F. (760&deg; C.) for about 3.0 to 10.5 hours to precipitate double gamma prime, furnace cooling the material about 50&deg; F. (28&deg; C.) to 100&deg; F. (56&deg; C.) per hour and heat treating the material at about 1200&deg; F. (649&deg; C.) for about 4.0 to about 12.5 hours.

Heat treatment for nickel-base alloys

The alloy consists of an age hardenable-corrosion resistant alloy useful for oil and gas applications that require resistance to low-level sour gas conditions. This alloy contains, by weight percent, 20 to 36 nickel, 18 to 25 chromium, 1 to 8 molybdenum, 1.2 to 4 titanium, less than 0.5 aluminum, 0.001 to 0.5 carbon, less than 1.5 niobium, less than 10 manganese, less than 5 copper, less than 4 cobalt, less than 0.1 total calcium, cerium and magnesium, 0 to 0.01 boron and balance iron and incidental impurities and deoxidizers.

High strength corrosion resistant alloy

A nickel-chromium-molybdenum-niobium alloy affords high resistance to aggressive corrosives, including chlorides which cause crevice corrosion and oxidizing acids which promote intergranular corrosion, the alloy also being readily weldable and possessing structural stability at very low as well as elevated temperatures. The alloy consists essentially of, (by weight), 19-23% Cr, 12-15% Mo, 2.25-4% W, 0.65-2% Nb, 2-8% Fe, balance Ni.

Corrosion resistant nickel-base alloy

A homogenizaton heat treatment for enhancing crevice and pitting corrosion resistance minimizes the formation of Mu phase in nickel-base alloys of high combined percentages of chromium, e.g., 19 to 23% and molybdenum, e.g., 14 to 17%, particularly together with tungsten. Also described is an advantageous alloy composition containing less than 2.5% iron, low carbon and a titanium to carbon ratio greater than 1 which is particularly adapted to be effectively treated by the homogenization heat treatment.

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Ona, WV, United States of America

Edward Lee Hibner