General Electric Company
Nickel-iron-cobalt based alloys and articles and methods for forming articles including nickel-iron-cobalt based alloys

Abstract:

Nickel-iron-cobalt based alloys are disclosed having sufficient castability for centrifugal casting essentially free from casting defects, cracking, and microstructure variability, and coefficients of thermal expansion up to about 9.times.10.sup.-6/.degree. C. for about 100-400.degree. C. and increasing from about 400-500.degree. C. to up to about 10.times.10.sup.-6/.degree. C., or up to about 6.times.10.sup.-6/.degree. C. between about 100-300.degree. C. and increasing from about 300-500.degree. C. to up to about 10.times.10.sup.-6/.degree. C. Articles are disclosed including unitary cast structures free of internal welds, brazing, and bolting, essentially annular conformations, diameters of at least about 500 mm, cross-sectional wall areas of at least about 2,000 mm.sup.2, and compositions including nickel-iron-cobalt based alloys. Methods for forming the articles are disclosed including rotating centrifugal molds with the compositions in molten states, forming the articles in near net shape.