Hitachi and Hitachi Metals have developed low thermal expansion Ni-base superalloy, Ni-20Cr-10Mo-1.2Al-1.6Ti alloy (USC141) for use as A-USC steam turbine material. The approximate 105 h creep rupture strength at 740° C is 100MPa, so USC141 can be expected to apply for blades and bolts. Now we have been studying to get better creep properties by microstructure controlling such as grain size or grain boundary morphology. In addition, the segregation test of USC141 shows good Freckle tendencies, it means that it would be easy to make a large ingot which could be used as rotors or pipes. From these calculation results, we have been tried to make an 850mmϕ ESR ingot of USC141.

creep rupture strength, grain size, microstructure, nickel-base superalloys, nickel-chromium-molybdenum-aluminum titanium alloys, steam turbine power plants, steam turbines, thermal expansion
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Copyright © 2011 ASM International. All rights reserved.
2011
ASM International
Topics
Microstructure Steam turbines Power plant equipment Superalloys Nickel-chromium-molybdenum alloys Creep rupture strength Thermal expansion
Issue Section:
Turbine Materials and Applications