Abstract: A method for manufacturing impellers is described. The method provides for manufacturing a plurality of tubular components, each tubular component forming an inner passage, which is shaped as one of the flow passages of the final impeller. The tubular components are assembled together forming a semi-finished impeller. The semi-finished impeller is provided with annular cavities extending around the rotation axis of the impeller and gaps between adjacent tubular components. The gaps and cavities are filled with metal powder and the semi-finished impeller is subject to hot isostatic pressing, to densify the metal powder and form a monolithic final impeller.

Abstract: The method of protecting a component of a turbomachine from liquid droplets erosion provides covering at least one region of a component surface exposed to a flow of a fluid containing a liquid phase to be processed by the turbomachine with a protective layer. The protective layer consists of a plurality of adjacent sub-layers of different materials having high hardness in the range of 1000-3000 HV and low fracture toughness below 20 MPam1/2. The materials are typically nitrides or carbides of titanium or aluminum or chromium or tungsten. In an embodiment, the covering is carried out by a PVD technique, in particular by Cathodic Arc PVD, or a CVD technique. The method may be applied to any component of turbomachines, but it may be particularly beneficial for parts of centrifugal compressors.

Abstract: A method for manufacturing impellers is described. The method provides for manufacturing a plurality of tubular components, each tubular component forming an inner passage, which is shaped as one of the flow passages of the final impeller. The tubular components are assembled together forming a semi-finished impeller. The semi-finished impeller is provided with annular cavities extending around the rotation axis of the impeller and gaps between adjacent tubular components. The gaps and cavities are filled with metal powder and the semi-finished impeller is subject to hot isostatic pressing, to densify the metal powder and form a monolithic final impeller.

Abstract: A method of manufacturing a component of a turbomachine by powder metal hot isostatic pressing is disclosed, which uses a container defining outside surfaces of the component. A metal insert is located inside the container before filling the container with metal powder, and the insert is left in the component after the end of its manufacturing. In an embodiment, a metal core is located inside the container before filling the container with metal powder, and the core is removed from the component before the end of its manufacturing. In this way, net shape surfaces may be obtained without manufacturing trials.

Abstract: The method of protecting a component of a turbomachine from liquid droplets erosion provides covering at least one region of a component surface exposed to a flow of a fluid containing a liquid phase to be processed by the turbomachine with a protective layer. The protective layer consists of a plurality of adjacent sub-layers of different materials having high hardness in the range of 1000-3000 HV and low fracture toughness below 20 MPam1/2. The materials are typically nitrides or carbides of titanium or aluminum or chromium or tungsten. In an embodiment, the covering is carried out by a PVD technique, in particular by Cathodic Arc PVD, or a CVD technique. The method may be applied to any component of turbomachines, but it may be particularly beneficial for parts of centrifugal compressors.

Abstract: Apparatus and method for decreasing the corrosion susceptibility and/or the liquid droplet erosion susceptibility of one or more turbine blades associated with a steam turbine. One or more of the turbine blades are constructed of an Austenitic Nitrogen strengthened stainless steel; such Austenitic stainless steel has a weight percentage of manganese bigger than ten and preferably a weight percentage of nickel smaller than five; advantageously, such Austenitic stainless steel is strengthened with nitrogen. The blades constructed of such Austenitic stainless steel are configured in the later stages of the steam turbine.

Abstract: Devices and methods provide for an impeller for use in a compressor. A method for manufacturing the impeller includes: attaching an intermediate layer to a base metal by placing a first metal powder into a gap between a first insert and the base metal; processing with hot isostatic pressing the base metal, the first metal powder and the first insert such that the intermediate layer is bonded to the base metal; attaching an external layer to the intermediate layer by placing a second powder into a gap between a second insert and the intermediate layer; processing the base metal, the intermediate layer, the second metal powder and the second insert via hot isostatic pressing such that the external layer is bonded to the intermediate layer; and removing the second insert to form the impeller, wherein the external layer is corrosion resistant.

Abstract: Methods and apparatuses for detecting corrosion in one or more blades of a gas turbine system includes a detection head having a shape that conforms to a surface geometry of a filet section of a gas turbine blade, whereby the detection head is operable to move along the axial length of the filet section for detecting corrosion pitting. At least one coil device located within the detection head induces a first magnetic field within an area of the filet in contact with the detection head. A receiver device is adapted to detect a signal corresponding to a second magnetic field received from the area of the filet exposed to the first magnetic field, where the second magnetic field is generated by induced currents in the area by the first magnetic field.

Abstract: Ultrasound inspection methods for noisy materials and related probes are disclosed to inspect a defect in a cast material that use polycarbonate delay layers having a first surface configured to be disposed on a surface of the cast material; and an acoustic crystal element disposed on a second surface of the polycarbonate delay layer.

Abstract: Devices and methods provide for an impeller for use in a compressor. A method for manufacturing the impeller includes: attaching an intermediate layer to a base metal by placing a first metal powder into a gap between a first insert and the base metal; processing with hot isostatic pressing the base metal, the first metal powder and the first insert such that the intermediate layer is bonded to the base metal; attaching an external layer to the intermediate layer by placing a second powder into a gap between a second insert and the intermediate layer; processing the base metal, the intermediate layer, the second metal powder and the second insert via hot isostatic pressing such that the external layer is bonded to the intermediate layer; and removing the second insert to form the impeller, wherein the external layer is corrosion resistant.

Abstract: Ultrasound inspection methods for noisy materials and related probes are disclosed to inspect a defect in a cast material that use polycarbonate delay layers having a first surface configured to be disposed on a surface of the cast material; and an acoustic crystal element disposed on a second surface of the polycarbonate delay layer.