Laser cladding of 0.4 mm and 0.8 mm wide knife edges made from 17-4PH stainless steel was investigated, using two types of powder and two different post heat treatments. Acceptable cladding deposits of 0.5 to 0.9 mm height were obtained on both sizes of knife edge, and with both powder types. Powder manufactured by water atomization was more difficult to feed during cladding, and produced a substantially higher oxide content in the deposited clad. The clad dimensional results showed that increasing laser energy density into the knife edges caused an increase in both clad build-up height and parent melt-back. An optimal energy density was established for a given knife edge width and powder feed rate, which produced the most efficient cladding deposit. Full solution heat treatment and aging was effective in producing a uniform hardness profile across the clad and substrate materials, while direct aging resulted in a non-uniform profile. This repair technique is applicable to a variety of labyrinth seals used in gas turbine engines.

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