Mechanical Performance of Various INCONEL® 740/740H Alloy Compositions for Use in A-USC Castings

The use of Ni-based superalloys as structural components of advanced ultra-supercritical steam and CO2 turbines is becoming necessary due to the increasing performance requirements of future power plant designs. Although numerous Ni-based superalloys can respond to the demanding mechanical performance, very few present a combination of high-strength and creep resistance while maintaining good ductility and weldability. Furthermore, the improved performance is often associated with wrought alloys while the fabrication of large castings is the primary target for those applications. With the comparatively lower mechanical properties of cast alloys, new designs based on compositional changes are necessary to allow for the use of Ni-based superalloys in A-USC castings. This lack of performance is primarily associated with the large and inhomogeneous grain size as well as elemental segregation and other casting anomalies. This investigation presents various alloys with compositions within the range of INCONEL® 740/740H designed to overcome the issues associated with the use of Ni-based superalloys in A-USC castings. Modifications to the chemistry were based on thermodynamic simulations and experimental results. Particular attention was given to reactive element additions, element partitioning, ʹ precipitate phase promoting elements and grain boundary carbides. The effects of the various compositional changes on the tensile and creep properties of INCONEL® 740/740H will be discussed.

Hastelloy G -30 / UNS N06035   HASTELLOY C-2000 (FOR SPRINGS)    Monel 404 (UNS N 04404)

Nimonic90        Nickel 2.4683 (Alloy 188)     Haynes˘ 214  Haynes 556 / UNS R30556 / 1.4883   Haynes 230® - 2.4733 - alloy 230  Monel 401 Metal piping   

 Hastelloy N / UNS N10003    Hastelloy B     Alloy 926 / 6Mo    alloy a 286 uns ss28286 1.498     alloy 28 UNS N08028, alloy 20 UNS N08020

INCOLOY® alloy 330    Incoloy 901® - 2.4975 - Alloy 901   Incoloy 028 1.4563 / Sanicro28    Inconel 693® - Alloy 693    Inconel 706   INCONEL® 740/740H Alloy

Hastelloy B-3 / UNS 10675 / 2.4600       Hastelloy C-4 / N06455 / 2.4610    Hastelloy X / N06002 / 2.4665        Monel 400 / UNS N04400 / 2.4360

 Monel K-500 / N05500 / 2.4375      Monel R-405 / N04405