Process for repairing water erosion damage of flow passage component of steam turbine and protecting flow passage component of steam turbine

Abstract

The invention discloses a process for repairing water erosion damage of a flow passage component of a steam turbine and protecting the flow passage component of the steam turbine. In the process, molded lines of the flow passage component of the steam turbine are repaired by adopting copy overlaying of manual argon tungsten arc welding aiming at the phenomenon of the water erosion damage existing in the flow passage component of the steam turbine. A water erosion resistant coating is prepared by supersonic speed flame spraying so as to achieve the purposes of repairing the molded lines of the flow passage component of the steam turbine and protecting the molded lines at large area on line and prolonging the service life of the flow passage component of the steam turbine. Through the process of the invention, the flow passage component of the steam turbine can be repaired and protected at large area on line in a short time without changing vibration characteristic, steam-driven characteristic and strength characteristic of the flow passage component of the steam turbine, so that the process has the advantages of high on-site operability, small deformation of the repaired workpiece, remarkable improvement on water erosion resistance and the like, can solve the common problem of water erosion in the flow passage component of the power station steam turbine in service on site, improves the running safety and efficiency of units and increases economic benefit of a power plant.

Description

technical field [0001] The invention relates to the technical field of material science, in particular to a process for repairing and protecting water erosion damage of flow-through parts of steam turbines. Background technique [0002] The steam turbine flow parts (mainly including blades, nozzles, baffles, etc.) in thermal power plants are the "heart" of the steam turbine system, and undertake the important task of converting steam flow energy into useful work. The flow parts of the steam turbine, especially the last stage moving blades, will be damaged by water erosion and have defects during operation. Water erosion of steam turbine blades refers to the phenomenon that the moving blades working in the wet steam region collide with the secondary water droplets entrained in the steam flow at high speed, resulting in damage and peeling off of the blade surface materials. Under normal circumstances, the areas where water erosion occurs on the blade are the steam inlet side ...

AI Technical Summary

Problems solved by technology

[0011] ① Due to the cracking of the cladding layer and the deformation of the substrate, the laser cladding process needs to be further improved;

[0012] ②The surface of the cladding layer is not smooth, the amount of subsequent machining is large, and defects such as cracks and holes are prone to appear at the junction of the alloy layer and the substrate, which brings great difficulties to practical applications;

[0013] ③ The fixed assets and maintenance costs of the laser processing system are relatively expensive compared with conventional repair technologies, which makes the cost of laser processed products higher

[0014] ④At present, most of the repair work adopts one-dimensional laser cladding method, which can only solve the repair problem of some parts

However, the equipment is relatively complicated and the operability is poor, so it is not suitable for on-site repair

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