A rotor for a turbomachine and a method of manufacturing the same. The method includes providing a lug with a lug body and an interface material disposed on the lug body. The method also includes friction welding the lug to a hub member via the interface material to define a projected structure for an outer radial area of a disc assembly of the rotor. The projected structure is configured to support a first side of a rotor blade of the rotor in cooperation with a second projected structure of the disc assembly supporting a second side of the rotor blade. The lug body and the hub member are made from different materials.

An unchamfered piston ring that is pre-treated by grit blasting to a defined roughness, followed by PVD coating with a metal nitride to a thickness of at least 10 m, leaving peaks and valleys in the coated piston ring. The coated piston ring is then lapped to remove the peaks without penetrating the coating, so that valleys and plateaus remain in the coated surface. The resulting piston ring exhibits superior coating retention due to the increased surface area created by the grit blasting, and yet also superior performance, as the cavities remaining increase the porosity of the coating and thus enhance the lubrication of the ring.

A method of joining a first work piece and a second workpiece. The first and second workpieces may be rotor wheels of a rotor for a turbomachine. At least one of the workpieces includes an oxide dispersion strengthened alloy material and the first and second work pieces may be joined by welding a cladding on at least one of the workpieces to the other of the workpieces, without welding a substrate of the at least one workpiece which includes an oxide dispersion strengthened alloy material.

A method of joining a first work piece and a second workpiece. The first and second workpieces may be rotor wheels of a rotor for a turbomachine. At least one of the workpieces includes an oxide dispersion strengthened alloy material and the first and second work pieces may be joined by welding a cladding on at least one of the workpieces to the other of the workpieces, without welding a substrate of the at least one workpiece which includes an oxide dispersion strengthened alloy material.

A method of forming a piston ring includes providing a base portion formed of a metallic material, the base portion having a first surface, and a second surface that is opposite the first surface, the base portion configured to interface with a piston ring groove. The method includes grinding the first surface to form a reference surface, applying a chromium layer to the second surface, and grinding the chromium layer to reduce a surface roughness of the chromium layer.

A method of forming a piston ring includes providing a base portion formed of a metallic material, the base portion having a first surface, and a second surface that is opposite the first surface, the base portion configured to interface with a piston ring groove. The method includes grinding the first surface to form a reference surface, applying a chromium layer to the second surface, and grinding the chromium layer to reduce a surface roughness of the chromium layer.

A piston ring that is pre-treated by grit blasting to a defined roughness, followed by PVD coating with a metal nitride to a thickness of at least 10 m, leaving peaks and valleys in the coated piston ring. The coated piston ring is then lapped to remove the peaks without penetrating the coating, so that valleys and plateaus remain in the coated surface. The resulting piston ring exhibits superior coating retention due to the increased surface area created by the grit blasting, and yet also superior performance, as the cavities remaining increase the porosity of the coating and thus enhance the lubrication of the ring.

A piston ring that is pre-treated by grit blasting to a defined roughness, followed by PVD coating with a metal nitride to a thickness of at least 10 m, leaving peaks and valleys in the coated piston ring. The coated piston ring is then lapped to remove the peaks without penetrating the coating, so that valleys and plateaus remain in the coated surface. The resulting piston ring exhibits superior coating retention due to the increased surface area created by the grit blasting, and yet also superior performance, as the cavities remaining increase the porosity of the coating and thus enhance the lubrication of the ring.

A piston ring that is pre-treated by grit blasting to a defined roughness, followed by PVD coating with a metal nitride to a thickness of at least 10 m, leaving peaks and valleys in the coated piston ring. The coated piston ring is then lapped to remove the peaks without penetrating the coating, so that valleys and plateaus remain in the coated surface. The resulting piston ring exhibits superior coating retention due to the increased surface area created by the grit blasting, and yet also superior performance, as the cavities remaining increase the porosity of the coating and thus enhance the lubrication of the ring.

A piston ring that is pre-treated by grit blasting to a defined roughness, followed by PVD coating with a metal nitride to a thickness of at least 10 m, leaving peaks and valleys in the coated piston ring. The coated piston ring is then lapped to remove the peaks without penetrating the coating, so that valleys and plateaus remain in the coated surface. The resulting piston ring exhibits superior coating retention due to the increased surface area created by the grit blasting, and yet also superior performance, as the cavities remaining increase the porosity of the coating and thus enhance the lubrication of the ring.