METHOD FOR RESTORING THE CHORD LINE OF THE FEATHER FROM A HEAT-RESISTANT NICKEL ALLOY Russian patent published in 2023 - IPC B23P6/00 

FIELD: turbomachinery.

SUBSTANCE: repair of cooled turbine blades of a gas turbine engine when restoring the chord line of the feather. The surfaces of the leading and trailing edges of the blade are prepared by removing the damaged base material, namely, heat-resistant nickel alloy ZhS6-K containing a reinforcing γ' phases 54%. Restoration of the chord line of the feather in the area of the leading and trailing edges is carried out by surfacing the coating with laser radiation in a shielding gas with simultaneous supply of powder filler material into the surfacing area. The powder filler material for restoring the leading and trailing edges of the feather is a cobalt-based heat-resistant alloy of the system Cr 30%, W 4.5%, Ni 1.2%, Si 2.5%, B≤0.1%, C 1,1%, F≤2%, fraction 40÷80 µm. A pulsed surfacing mode is used, in which each laser radiation pulse is made with amplitude modulation of the laser radiation power pulse shape, while each modulated laser radiation pulse consists of a leading edge of a pulse with a power density for surfacing and a trailing edge of a pulse with a power density lower than the power density leading edge of the pulse by 25÷30%, for concurrent heating of the surfacing zone to a temperature lower than the melting temperature of the heat-resistant nickel alloy of the blade by 300-350°C, excluding cracking of the surfacing layer. Then, the surfacing surfaces of the blade are machined to the dimensions specified in the drawing. After that, pack aluminizing is carried out by applying aluminium paint to the restored leading and trailing edges of the feather. Next, high-temperature diffusion annealing is carried out in a vacuum furnace at a temperature of 1000°C. The surfacing zone is protected locally with a shielding gas flow rate of 6-7 l/min. Apply fluorescent penetrant examination.

EFFECT: high-quality restoration of the leading and trailing edges of the feather made of heat-resistant nickel alloy, yield of good blades after repair, increase in the life cycle of the restored parts, restoration of the chord line of the feather, feather width and density, and restoration of the turbine stage efficiency to the optimum.

5 cl, 3 dwg