Abstract: A welding apparatus includes a workpiece housing having a window therethrough and having a welding access therethrough for a welder to an interior of the workpiece housing. The workpiece housing is metallic with a heat insulation on an internal surface thereof. A lamp heat source is directed through the window and at the workpiece in the interior of the workpiece housing. A gas source delivers a controllable flow of a shielding gas to the interior of the workpiece housing. A temperature sensor senses a temperature of the workpiece within the interior of the workpiece housing. A feedback controller controls the power to the lamp heat source responsive to the temperature of the workpiece. To perform welding, the workpiece is placed into the interior of the workpiece housing so as to have its temperature sensed by the temperature sensor, and the gas source is operated to envelope the workpiece in the shielding gas.

Abstract: A method is provided for repairing a turbine nozzle segment having at least one vane disposed between outer and inner bands. The method includes separating the inner band from the nozzle segment, and joining the inner band to a newly manufactured replacement casting having an outer band and a vane. The replacement casting includes an airfoil stub. The airfoil stub is received in a recess formed in the inner band. Joining is completed by joining the airfoil stub to the inner band. The replacement casting may be modified from a newly manufactured singlet casting.

Abstract: A method for repairing a turbine nozzle segment having at least one vane disposed between outer and inner bands includes separating the inner band from the nozzle segment, and joining the inner band to a newly manufactured replacement casting having an outer band and at least one vane. The replacement casting includes a mounting platform formed on one end of the vane and a boss formed on the mounting platform. A collar is joined to the inner band and has a slot formed therein. The boss is then inserted into the slot, and the mounting platform is received in a recess formed in the inner band. Joining is completed by joining the boss to the collar and the mounting platform to the inner band.