Method of remanufacturing turbine vane clusters for gas turbine engines

Claim 1

A method for remanufacturing turbine vane clusters of the type having two or more coated vanes extending between a common inner platform and a common outer platform, comprising the steps of: inspecting damaged vane clusters and selecting complementary vanes and contiguous platforms for combination into a reconstructed cluster; stripping the coating materials from the selected vanes and from the portions of the platforms contiguous thereto; relieving residual stresses in the entire vane clusters in which the selected vanes are contained prior to the step of separating the selected vanes from the clusters; separating the selected vanes and the portions of the platforms contiguous thereto from the vane clusters after the step of relieving stresses from the vane clusters; machining bond faying surfaces on the platforms of the complementary vanes selected for combination; cleaning the machined faying surfaces; bonding the complementary vanes at the faying surfaces to form a reconstructed vane cluster; solution heat treating the reconstructed vane cluster; applying corrosion resistant coating to surfaces of the vane cluster which are to be exposed to hot working medium gases; precipitation hardening the coated vane cluster.

Claim 2

A method for remanufacturing turbine vane clusters of the type having two or more coated vanes extending between a common inner platform and a common outer platform, comprising the steps of: inspecting damaged vane clusters and selecting complementary vanes and contiguous platforms for combination into a reconstructed cluster; stripping the coating materials from the selected vanes and from the portions of the platforms contiguous thereto; relieving residual stresses in the entire vane clusters in which the selected vanes are contained prior to the step of separating the selected vanes from the clusters; separating the selected vanes and the portions of the platforms contiguous thereto from the vane clusters after the step of relieving stresses from the vane clusters; machining bond faying surfaces on the platforms of the complementary vanes selected for combination; cleaning the machined faying surfaces; bonding the complementary vanes at the faying surfaces to form a reconstructed vane cluster; solution heat treating the reconstructed vane cluster; applying corrosion resistant coating to surfaces of the vane cluster which are to be exposed to hot working medium gases; precipitation hardening the coated vane cluster.

Claim 3

A method for remanufacturing turbine vane clusters of the type cast of MAR-M-200+Hf alloy and coated with an aluminide corrosion resistant coating, comprising the steps of: inspecting damaged vane clusters and selecting complementary vanes and contiguous platforms for combination to form a reconstructed vane cluster; removing all appendages attached to the castings: stripping the aluminide coating from the selected vanes by grit blasting the coated surfaces and immersing the clusters in a nitric acid solution until the coating is removed; relieving residual stresses in the vane clusters by heating the clusters in an argon atmosphere for two (2) hours at two thousand two hundred degrees Fahrenheit (2200° F.); separating the selected vanes and contiguous platforms from the damaged vane clusters; inspecting the separated vanes for distortion and correcting any such distortion by mechanically deforming the vane at temperatures up to two thousand degrees Fahrenheit (2000° F.); machining bond faying surfaces on the platforms of the complementary vanes; cleaning the bond faying surfaces; bonding the complementary vanes at the faying surfaces; solution heat treating the bonded vanes in an argon atmosphere at two thousand two hundred degrees Fahrenheit (2200° F.) for two (2) hours; applying aluminide, corrosion resistant coating to surfaces of the cluster which are to be exposed to hot working medium gases; precipitation heat treating the bonded vanes in or at sixteen hundred degrees Fahrenheit (1600° F.) for thirty-two (32) hours.

Claim 4

A method for remanufacturing turbine vane clusters of the type cast of MAR-M-200+Hf alloy and coated with an aluminide corrosion resistant coating, comprising the steps of: inspecting damaged vane clusters and selecting complementary vanes and contiguous platforms for combination to form a reconstructed vane cluster; removing all appendages attached to the castings: stripping the aluminide coating from the selected vanes by grit blasting the coated surfaces and immersing the clusters in a nitric acid solution until the coating is removed; relieving residual stresses in the vane clusters by heating the clusters in an argon atmosphere for two (2) hours at two thousand two hundred degrees Fahrenheit (2200° F.); separating the selected vanes and contiguous platforms from the damaged vane clusters; inspecting the separated vanes for distortion and correcting any such distortion by mechanically deforming the vane at temperatures up to two thousand degrees Fahrenheit (2000° F.); machining bond faying surfaces on the platforms of the complementary vanes; cleaning the bond faying surfaces; bonding the complementary vanes at the faying surfaces; solution heat treating the bonded vanes in an argon atmosphere at two thousand two hundred degrees Fahrenheit (2200° F.) for two (2) hours; applying aluminide, corrosion resistant coating to surfaces of the cluster which are to be exposed to hot working medium gases; precipitation heat treating the bonded vanes in or at sixteen hundred degrees Fahrenheit (1600° F.) for thirty-two (32) hours.