STATUS OF PRECIPITATION HARDENED NICKEL BASE ALLOYS INCLUDING 718 FOR OILFIELD APPLICATIONS

This paper describes typical upstream oilfield applications for 718 and similar precipitation hardened nickel base alloys. These include products in the drilling, completion and production segments of the upstream market. The discussion of applications is accompanied with current understanding of the limitations and regulations affecting applications of these alloys. A contrast is presented between the precipitation hardenable and cold worked nickel alloys with respect to applications and performance limitations. The different market segments with the relevant applications exhibit different failure mechanisms. A discussion is presented that illustrates where the various failure mechanisms are found and the factors that have been identified that affect the risk of occurrence. Some metallurgical factors that we know affect the susceptibility of these alloys to the failure mechanisms are presented. The last subject discussed is the future with respect to these alloys. The expected changes in the operating conditions and applications are identified with the associated hurdles that will need to be overcome. These projections provide some direction to the Oil & Gas Industry and the alloy manufacturers that supply them.