Nickel base precipitation hardened alloys having improved resistance stress corrosion cracking

US4755240A · kind A · utility

Assignees

• Exxon Production Research Company · US
• Exxon Research and Engineering Company · US

Inventors

• Reghavan Ayer · Stamford, US
• Glen A. Vaughn · Sedona, US
• Lawrence J. Sykes · Houston, US

Key dates

• Filing date: May 12, 1986
• Grant date: Jul 5, 1988
• Expiry date: May 12, 2006

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C19/055
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The present invention provides Ni (and/or Co) base precipitation hardened alloy compositions having improved resistance to stress corrosion cracking and being comprised of: PA0 12-25 wt. % Cr; PA0 0-10 wt. % Mo; PA0 0-12 wt. % W, with the proviso that Mo+0.5 W is .gtoreq.2 wt. % and .ltoreq.10 wt. % and with the proviso that Cr+Mo+0.5 W is .ltoreq.28 wt. %; PA0 2-6 wt. % of one or more of Al, Nb, and Ti; PA0 <0.05 wt. % C; PA0 <0.05 wt. % O; PA0 <0.05 wt. % N; and the balance being Ni (and/or Co) and any incidental impurities, wherein the concentrations of Ni (and/or Co), Cr and Mo (and/or W) are correlated so that their combination represents a point within the area ABCD of FIG. 1 hereof. Preferably, the ratio, expressed in atomic percent, of Al to Nb+Ti is between about 0 and 4.0, preferably between about 0.8 and 1.5, more preferably about 1. In addition, Hf is preferably included in a concentration, expressed in weight percent, of between about 10 (C+O+N) and 30 (C+O+N), more preferably between about 15 (C+O+N) and 20 (C+O+N). Up to 30 wt. % of the Ni (and/or Co) can be replaced with Fe, depending on the severity of the stress corrosion environment.