Patent ID: 7591410

Claim:
A method for welding together two metal pieces, comprising: buttering a surface of a first metal piece with a first nickel-based filler metal at a thickness sufficient to isolate a heat-affected zone in the first metal piece from subsequent welding to produce a first buttered surface; heat-treating at least the heat-affected zone in the first metal piece after said buttering of the surface of the first metal piece to produce a heat-treated first buttered surface; buttering a surface of a second metal piece with a second nickel-based filler metal having the same composition as the first nickel-based filler metal and at a thickness sufficient to isolate a heat-affected zone in the second metal piece from subsequent welding to produce a second buttered surface; heat-treating at least the heat-affected zone in the second metal piece after said buttering of the surface of the second metal piece to produce a heat-treated second buttered surface; and welding the heat-treated first buttered surface to the heat-treated second buttered surface with a third nickel-based filler metal having the same composition as the first and second nickel-based filler metals.