Nickel-base alloy and its use in casting and welding operations

Abstract

An alloy has a composition of, in weight percent, from about 16 percent to about 21 percent chromium, from about 6 percent to about 12 percent iron, from about 6 percent to about 12 percent cobalt, from about 2.8 percent to about 3.3 percent molybdenum, from about 5 percent to about 5.4 percent niobium, from 0 to about 2 percent tantalum, from about 0.65 percent to about 1.15 percent titanium, from about 0.2 percent to about 0.8 percent aluminum, from about 0.01 percent to about 0.05 percent carbon, from about 0.005 percent to about 0.01 percent boron, less than about 0.1 percent zirconium, balance nickel and impurities. A molten mass of this composition may be cast into a mold for solidification. The solid material may be welded either in a rework/repair process or to join it to a second article.

What is claimed is:  
     
         1 . A composition of matter having a composition consisting essentially of, in weight percent, from about 16 percent to about 21 percent chromium, from about 6 percent to about 12 percent iron, from about 6 percent to about 12 percent cobalt, from about 2.8 percent to about 3.3 percent molybdenum, from about 5 percent to about 5.4 percent niobium, from zero to about 2 percent tantalum, from about 0.65 percent to about 1.15 percent titanium, from about 0.2 percent to about 0.8 percent aluminum, from about 0.01 percent to about 0.05 percent carbon, from about 0.005 percent to about 0.01 percent boron, less than about 0.1 percent zirconium, balance nickel and impurities.  
     
     
         2 . The composition of matter of  claim 1 , wherein the tantalum content is less than about 1 percent.  
     
     
         3 . The composition of matter of  claim 1 , wherein the total of iron plus cobalt is from about 17 to about 19 percent.  
     
     
         4 . The composition of matter of  claim 1 , wherein the iron content is from about 8 percent to about 9.5 percent.  
     
     
         5 . The composition of matter of  claim 1 , wherein the chromium content is about 18 percent, the iron content is about 9 percent, the cobalt content is about 9 percent, the molybdenum content is about 3 percent, the niobium content is about 5 percent, the tantalum content is less than about 0.01 percent, the titanium content is about 1 percent, the aluminum content is about 0.5 percent, the carbon content is about 0.03 percent, and the boron content is about 0.007 percent.  
     
     
         6 . A method of providing a cast article, comprising the steps of: 
 providing a molten mass of metal having a composition consisting essentially of, in weight percent, from about 16 percent to about 21 percent chromium, from about 6 percent to about 12 percent iron, from about 6 percent to about 12 percent cobalt, from about 2.8 percent to about 3.3 percent molybdenum, from about 5 percent to about 5.4 percent niobium, from 0 to about 2 percent tantalum, from about 0.65 percent to about 1.15 percent titanium, from about 0.2 percent to about 0.8 percent aluminum, from about 0.01 percent to about 0.05 percent carbon, from about 0.005 percent to about 0.01 percent boron, less than about 0.1 percent zirconium, balance nickel and impurities; and    casting molten mass of metal into a mold to form the cast article.    
     
     
         7 . The method of  claim 6 , including an additional step, after the step of casting, of hot isostatic pressing the cast article.  
     
     
         8 . The method of  claim 6 , including an additional step, after the step of casting, of heat treating the cast article.  
     
     
         9 . The method of  claim 6 , wherein the step of providing the billet includes the step of providing the billet having an iron content of from about 8 percent to about 9.5 percent.  
     
     
         10 . The method of  claim 6 , including an additional step, after the step of casting, of placing the cast article into service at a maximum service temperature of at least about 1300° F.  
     
     
         11 . The method of  claim 6 , including an additional step, after the step of casting, of welding the cast article.  
     
     
         12 . A method of preparing a welded article, comprising the steps of: 
 providing a piece of material having a composition consisting essentially of, in weight percent, from about 16 percent to about 21 percent chromium, from about 6 percent to about 12 percent iron, from about 6 percent to about 12 percent cobalt, from about 2.8 percent to about 3.3 percent molybdenum, from about 5 percent to about 5.4 percent niobium, from 0 to about 2 percent tantalum, from about 0.65 percent to about 1.15 percent titanium, from about 0.2 percent to about 0.8 percent aluminum, from about 0.01 percent to about 0.05 percent carbon, from about 0.005 percent to about 0.01 percent boron, less than about 0.1 percent zirconium, balance nickel and impurities; and    welding the piece of material to form the welded article.    
     
     
         13 . The method of  claim 12 , including an additional step, after the step of welding, of heating treating the welded article.  
     
     
         14 . The method of  claim 12 , wherein the step of providing includes the step of providing the piece of cast material.  
     
     
         15 . The method of  claim 12 , wherein the step of welding includes the step of surface welding the piece of material.  
     
     
         16 . The method of  claim 12 , wherein the step of welding includes the step of joining the piece of material to a second piece of material.