Abstract: A process and alloy for producing a turbine blade whose properties enable the blade to operate within a steam turbine at maximum operating temperatures of greater than 1300° F. (about 705° C.). The process includes casting the blade from a gamma prime-strengthened nickel-base superalloy having a composition of, by weight, 14.25-15.75% cobalt, 14.0-15.25% chromium, 4.0-4.6% aluminum, 3.0-3.7% titanium, 3.9-4.5% molybdenum, 0.05-0.09% carbon, 0.012-0.020% boron, maximum 0.5% iron, maximum 0.2% silicon, maximum 0.15% manganese, maximum 0.04% zirconium, maximum 0.015% sulfur, maximum 0.1% copper, balance nickel and incidental impurities, and an electron vacancy number of 2.32 maximum. The casting then undergoes a high temperature solution heat treatment to promote resistance to hold-time cracking. The blade exhibits a combination of yield strength, stress rupture properties, environmental resistance, and cost in steam turbine applications to 1400° F. (about 760° C.).

Abstract: A process and alloy for producing a turbine blade whose properties enable the blade to operate within a steam turbine at maximum operating temperatures of greater than 1300° F. (about 705° C.). The process includes casting the blade from a gamma prime-strengthened nickel-base superalloy having a composition of, by weight, 14.25-15.75% cobalt, 14.0-15.25% chromium, 4.0-4.6% aluminum, 3.0-3.7% titanium, 3.9-4.5% molybdenum, 0.05-0.09% carbon, 0.012-0.020% boron, maximum 0.5% iron, maximum 0.2% silicon, maximum 0.15% manganese, maximum 0.04% zirconium, maximum 0.015% sulfur, maximum 0.1% copper, balance nickel and incidental impurities, and an electron vacancy number of 2.32 maximum. The casting then undergoes a high temperature solution heat treatment to promote resistance to hold-time cracking. The blade exhibits a combination of yield strength, stress rupture properties, environmental resistance, and cost in steam turbine applications to 1400° F. (about 760° C.).

Abstract: A component made of an alloy including carbon at less than approximately 0.04 weight percent, manganese at about 0.0 to about 0.2 weight percent, silicon at about 0.0 to about 0.25 weight percent, phosphorus at about 0.0 to about 0.015 weight percent, sulfur at about 0.0 to about 0.015 weight percent, chromium from about 20.0 to about 23.0 weight percent, molybdenum from about 8.5 to about 9.5 weight percent, niobium from about 3.25 to about 4 weight percent, tantalum at about 0.0 to about 0.05 weight percent, titanium from about 0.2 to about 0.4 weight percent, aluminum from about 0.15 to about 0.3 weight percent, iron from about 3.0 to about 4.5 weight percent, and the remainder being nickel. The alloy may then be subjected to heat treatment procedures such as annealing at a temperature of less than approximately 982° C. and a duration of less than approximately one hour and aging at a temperature between approximately 538° C. and 760° C. and a duration of up to approximately 100 hours.