Cavitation repair method for blades of water turbine

Abstract

The invention discloses a cavitation repair method for blades of a water turbine. The method includes the steps that firstly, the blades of the water turbine are washed to remove rust, the cavitation portions of the blades are preheated through large-spot short-pulse high-power laser beams and melt-cladding laser beams are then used for melt-cladding treatment; in the melt-cladding process, the melt-cladding portions are impacted regularly through large-power short-pulse laser beams, so that cavitation micro-holes are full of melted metal liquid; melt-cladding regions are impacted through large-power lasers after melt-cladding treatment is performed; and the metallographic structures of the melt-cladding regions are refined through impact waves generated by laser irradiation. By the adoption of the method, when cavitation repair of the blades is performed, no mechanical grinding is needed, body materials of the blades are kept as many as possible, and the repair workload is reduced; in the melt-cladding process, the cavitation micro-holes are filled with a melt-cladding material through impact vibration, so that the phenomenon that sand holes exist in the repaired blades is avoided; and furthermore, the metallographic structures of the melt-cladding layers are refined through impact refinement, and the service life of the blades can be prolonged through the strength of the melt-cladding layers.

Description

technical field [0001] The invention relates to the field of remanufacturing, in particular to the repairing and remanufacturing of water turbine blades. Background technique [0002] Turbine blades are an important component in the hydropower industry. Cavitation is one of the main forms of blade failure. Conventional blade cavitation repair methods mainly include alloy surfacing, plasma surfacing or spraying, argon arc welding, and laser cladding. Wait. [0003] For example, the Chinese invention patent with application number 200710118944.9 discloses a laser in-situ repair method for steam turbine cavitation blades. It uses the beam emitted by the laser to repair the cavitation surface of the blades. This method realizes the steam turbine blades with narrow gaps without disassembly. In situ repair under. The Chinese invention patent with the application number 201310579011.5 discloses a method for depositing a hard coating with a pulse electrode on a stainless steel wat...

AI Technical Summary

Problems solved by technology

[0004] At present, the cavitation part of the blade is usually in the form of a honeycomb. Before repairing and remanufacturing, mechanical grinding is required to remove the honeycomb structure, and then surfacing or melting is performed. When the cavitation is serious, completely removing the honeycomb structure will increase the repair cost The workload and the strength of the blade body are weakened, and the deformation of the blade is large during welding or cladding; if the honeycomb structure is not removed clearly, micropores are left on the blade surface. Due to the scale effect, it is difficult to fill the filling material during cladding. Micropores, leaving sand holes in the repaired blades, reducing the strength of the blades

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