Nickel-based superalloy, process therefor, and components formed therefrom

Abstract

A gamma prime nickel-based superalloy suitable for producing structural components ( 10 ), for example, turbine disks ( 10 ) and other turbomachinery components. The superalloy comprises an intentional amount of iron of up to 2.0% and is preferably capable of exhibiting structural properties comparable to nickel-based superalloys without iron. The superalloy can be made using processes that lend themselves to advantageous scrap and revert usage of iron-containing alloys. The superalloy is free of an observable amount of sigma phase.

What is claimed is: 
     
         1 . A gamma prime nickel-base superalloy comprising a composition that
 falls within the compositional space defined by, by weight, about 15.0-17.0% chromium, about 12.0-14.0% cobalt, about 3.5-4.5% molybdenum, about 3.5-4.5% tungsten, about 1.5-2.5% aluminum, about 3.2-4.2% titanium, about 0.5-1.0% niobium, about 0.010-0.060% carbon, about 0.010-0.060% zirconium, about 0.010-0.040% boron, about 0.0-0.3% hafnium, about 0.0-0.01 vanadium, and about 0.0-0.01 yttrium, the balance nickel and incidental impurities, the superalloy further containing iron in an amount exceeding an impurity level and up to 2.0%, the superalloy being free of an observable amount of sigma phase.   
     
     
         2 . A component ( 10 ) formed of the gamma prime nickel-base superalloy according to  claim 1 . 
     
     
         3 . The component ( 10 ) according to  claim 2 , wherein the component ( 10 ) is a turbine disk, compressor disk, blisk, seal, shaft or retainer. 
     
     
         4 . A process of producing the component ( 10 ) according to  claim 2 , the process comprising at least one step chosen from the group consisting of:
 adding at least one iron-containing alloy to raw materials and melting the iron-containing alloy and the raw materials to produce the superalloy;   adding at least one iron-containing scrap alloy to raw materials and melting the iron-containing scrap alloy and the raw materials to produce the superalloy; and   melting the superalloy using melt equipment immediately previously used to melt an iron-containing alloy without cleaning the melt equipment to remove remnants of the iron-containing alloy.   
     
     
         5 . A process of producing the gamma prime nickel-base superalloy of  claim 1 , wherein the process comprises at least one step chosen from the group consisting of:
 adding at least one iron-containing alloy to raw materials and melting the iron-containing alloy and the raw materials to produce the superalloy;   adding at least one iron-containing scrap alloy to raw materials and melting the iron-containing scrap alloy and the raw materials to produce the superalloy; and   melting the superalloy using melt equipment immediately previously used to melt an iron-containing alloy without cleaning the melt equipment to remove remnants of the iron-containing alloy.   
     
     
         6 . The process according to  claim 5 , wherein the at least one iron-containing alloy comprises, by weight, 50-55% nickel, 17-21% chromium, 2.8-3.33% molybdenum, 4.75-5.5% niobium, 0-1.0% cobalt, 0.65-1.15 titanium, 0.2-0.8% aluminum, 0-0.35% manganese, 0-0.3% copper, 0-0.08% carbon, 0-0.006% boron, the balance iron and incidental impurities. 
     
     
         7 . The gamma prime nickel-base superalloy according to  claim 1 , the composition thereof consisting of, by weight:
 15.8 to 16.2% chromium;   12.9 to 13.3% cobalt;   3.95 to 4.1% molybdenum;   3.9 to 4.1% tungsten;   2.01 to 2.24% aluminum;   3.6 to 3.9% titanium;   0.67 to 0.74% niobium;   0.012 to 0.02% boron;   0.005 to 0.011% carbon;   0.02 to 0.06% zirconium;   0.0-0.3% hafnium;   0.0-0.01 vanadium;   0.0-0.01 yttrium;   0-0.0035% nitrogen; and   iron in an amount exceeding an impurity level and up to 1.34%;   the balance essentially nickel and incidental impurities.   
     
     
         8 . A component ( 10 ) formed of the gamma prime nickel-base superalloy according to  claim 7 . 
     
     
         9 . A process of producing the component ( 10 ) according to  claim 8 , the process comprising at least one step chosen from the group consisting of:
 adding at least one iron-containing alloy to raw materials and melting the iron-containing alloy and the raw materials to produce the superalloy;   adding at least one iron-containing scrap alloy to raw materials and melting the iron-containing scrap alloy and the raw materials to produce the superalloy; and   melting the superalloy using melt equipment immediately previously used to melt an iron-containing alloy without cleaning the melt equipment to remove remnants of the iron-containing alloy.   
     
     
         10 . The component ( 10 ) according to  claim 8 , wherein the component ( 10 ) is a turbine disk ( 10 ), compressor disk, blisk, seal, shaft, or retainer. 
     
     
         11 . A process of producing the component ( 10 ) according to  claim 10 , the process comprising at least one step chosen from the group consisting of:
 adding at least one iron-containing alloy to raw materials and melting the iron-containing alloy and the raw materials to produce the superalloy;   adding at least one iron-containing scrap alloy to raw materials; and melting the iron-containing scrap alloy and the raw materials to produce the superalloy; and   melting the superalloy using melt equipment immediately previously used to melt an iron-containing alloy without cleaning the melt equipment to remove remnants of the iron-containing alloy.   
     
     
         12 . The gamma prime nickel-base superalloy according to  claim 1 , wherein the superalloy contains, by weight, about 0.6 to about 1.34% iron. 
     
     
         13 . A process of producing a gamma prime nickel-base superalloy consisting of, by weight:
 12.9 to 13.3% cobalt;   15.8 to 16.2% chromium;   3.95 to 4.1% molybdenum;   3.9 to 4.1% tungsten;   2.01 to 2.24% aluminum;   3.6 to 3.9% titanium;   0.6 to 0.8% niobium;   0.012 to 0.02% boron;   0.005 to 0.011% carbon;   0.02 to 0.06% zirconium;   0.0-0.3% hafnium;   0.0-0.01 vanadium;   0.0-0.01 yttrium;   0-0.0035% nitrogen; and   iron in an amount exceeding an impurity level and up to 1.34%;   the balance essentially nickel and impurities;   wherein the process comprises at least one step chosen from the group consisting of:   adding at least one iron-containing alloy to raw materials and melting the iron-containing alloy and the raw materials to produce the superalloy;   adding at least one iron-containing scrap alloy to raw materials and melting the iron-containing scrap alloy and the raw materials to produce the superalloy; and   melting the superalloy using melt equipment immediately previously used to melt an iron-containing alloy without cleaning the melt equipment to remove remnants of the iron-containing alloy.   
     
     
         14 . The process according to  claim 13 , wherein the at least one iron-containing alloy comprises multiple iron-containing alloys. 
     
     
         15 . The process according to  claim 13 , wherein the at least one iron-containing alloy comprises, by weight, 50-55% nickel, 17-21% chromium, 2.8-3.33% molybdenum, 4.75-5.5% niobium, 0-1.0% cobalt, 0.65-1.15 titanium, 0.2-0.8% aluminum, 0-0.35% manganese, 0-0.3% copper, 0-0.08% carbon, 0-0.006% boron, the balance iron and incidental impurities.