Pre-weld heat treatment of γ' precipitation strengthened nickel-based superalloys
This technology relates to a method for improving the weldability of nickel-based superalloys. The method involves pre-weld heat treating a nickel-based superalloy, such as INCONEL 738 (IN 738) at a temperature sufficient to dissolve any borides that might have formed during casting and prior to processing. The heated nickel-based superalloy is then slowly cooled at a rate that is slow enough to minimize further boron segregation. By minimizing boron segregation at grain boundaries and eliminating boride formation in the treated pre-weld nickel-based superalloy, resistance to intergranular heat-affect zone (HAZ) liquation cracking is improved and a pre-weld microstructure that exhibits the desirable hardness and ductility properties suitable for welding are achieved.
美国
