Process for manufacturing high strength corrosion resistant alloy for oil patch applications
AssigneeHuntington Alloys, Inc.
InventorsSarwan K. Mannan, Brett Clark Puckett
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Abstract
A Ni—Fe—Cr alloy having high strength, ductility and corrosion resistance especially for use in deep-drilled, corrosive oil and gas well environments, as well as for marine environments. The alloy comprises in weight %: 35-55% Ni, 12-25% Cr, 0.5-5% Mo, up to 3% Cu, 2.1-4.5% Nb, 0.5-3% Ti, up to 0.7% Al, 0.005-0.04% C, balance Fe plus incidental impurities and deoxidizers. The alloy must also satisfy the ratio of (Nb−7.75 C)/(Al+Ti)=0.5-9 in order to obtain the desired high strength by the formation of γ′ and γ″ phases. The alloy has a minimum of 1% by weight γ″ phase dispersed in its matrix for strength purposes and a total weight percent of γ′+γ″ phases being between 10 and 30.
Claims6
A process for manufacturing a high strength corrosion resistant alloy comprising the steps of:
- providing an alloy consisting essentially of, in percent by weight:
- 35-55% Ni, 12-25% Cr, 0.5-5% Mo, 0.2-3% Cu, 2.2-4.5% Nb, 0.5-3% Ti, up to 0.7% Al, 0.005-0.04% C, 16-35% Fe, plus incidental impurities and deoxidizers and wherein the alloy satisfies the equation:
- (
- Nb
- -
- 7.75
-
-
- C
- )
- (
- Al
- +
- Ti
- )
- =
- 0.5
-
-
- to
-
-
- 9
- and heat treating the alloy by annealing, water quenching and at least one age hardening step, whereby the alloy contains a mixture of γ′ and γ″ phases with a minimum of 1% by weight γ″ phase and has a minimum yield strength of 120 ksi when said alloy is in the annealed, water quenched, and age hardened condition and suited for use in sour gas and oil well environments.
Dependencies are inferred from the claim text.