Patent ID: 7322396

Claim:
A method for fabricating a hollow airfoil, comprising the steps of providing a casting mold assembly comprising a casting mold with an inner wall, a casting core that is received within the inner wall of the casting mold to leave a casting space between an outer wall of the casting core and the inner wall of the casting mold, wherein the casting space defines a portion of the hollow airfoil, and a standoff spacer that prevents the casting core from contacting the inner wall of the casting mold and thereby maintains the casting space; casting a nickel-base superalloy casting alloy into the casting space and solidifying the cast nickel-base superalloy casting alloy to form the hollow airfoil; separating the hollow airfoil from the casting mold assembly; identifying the presence of a through hole extending through a wall of the hollow airfoil that is present due to the standoff spacer; and, if there is a through hole present, welding the through hole by closing the through hole with a weld alloy different from the casting alloy and selected from the group consisting of (1) an alloy having a nominal composition, in weight percent, 0.01-0.03 percent carbon, 0.1 percent maximum manganese, 0.5-0.6 percent silicon, 0.01 percent maximum phosphorus, 0.004 percent maximum sulfur, 7.4-7.8 percent chromium, 2.9-3.3 percent cobalt, 0.10 percent maximum molybdenum, 3.7-4.0 percent tungsten, 5.3-5.6 percent tantalum, 0.02 percent maximum titanium, 7.6-8.0 percent aluminum, 1.5-1.8 percent rhenium, 0.005 percent maximum selenium, 0.3 percent maximum platinum, 0.01-0.02 percent boron, 0.03 percent maximum zirconium, 0.12-0.18 percent hafnium, 0.1 percent maximum niobium, 0.1 percent maximum vanadium, 0.1 percent maximum copper, 0.2 percent maximum iron, 0.0035 percent maximum magnesium, 0.01 percent maximum oxygen, 0.01 percent maximum nitrogen, balance nickel with other elements 0.5 percent maximum; (2) an alloy having a nominal composition in weight percent of about 7.5 percent cobalt, about 7.0 percent chromium, about 1.5 percent molybdenum, about 5 percent tungsten, about 3 percent rhenium, about 6.5 percent tantalum, about 6.2 percent aluminum, about 0.15 percent hafnium, about 0.05 percent carbon, about 0.004 percent boron, about 0.01 percent yttrium, balance nickel and minor elements; and (3) an alloy having a nominal composition in weight percent of about 12.0 percent cobalt, about 6.8 percent chromium, about 1.5 percent molybdenum, about 4.9 percent tungsten, about 2.8 percent rhenium, about 6.35 percent tantalum, about 6.15 percent aluminum, about 1.5 percent hafnium, about 0.12 percent carbon, about 0.015 percent boron, balance nickel and minor elements.