With the continuous development of modern science, technology, and industry, the working environment of parts and components is becoming more and more complex, and the requirements for surface properties are getting higher and higher. Therefore, the scrap rate of parts has greatly increased. Parts that are usually scrapped due to surface failure include rotor blades, shaft parts, gear parts, molds, etc.
Parts with only surface damage can be repaired under the condition that the overall performance of the parts meets the working conditions. If parts scrapped due to misprocessing or service damage can be repaired, not only can huge economic and time losses be recovered, but also resource utilization can be improved, which is in line with the world’s sustainable development strategy.
The method of repairing parts can be laser cladding repair. It is based on the working conditions of the workpiece, laser cladding metal with various design components to prepare a heat-resistant, corrosion-resistant, wear-resistant, oxidation-resistant, fatigue-resistant, or light, and Surface coating layer with electrical and magnetic properties. Laser cladding repair is a rapid cooling process. During the cladding process, the heat input to the repaired workpiece is small, the heat-affected zone is small, the cladding layer has a fine structure, and it is easy to implement automation. Therefore, laser cladding is used for repair. Components such as rotors offer greater advantages than other methods. Laser cladding technology solves a series of technical problems such as thermal deformation and thermal fatigue damage that are inevitable during thermal processing such as traditional electric welding and argon arc welding. It also solves the bonding strength between the coating and the substrate during cold processing such as traditional electroplating and spraying. Poor contradiction, which provides a good way for surface repair.
Rotor blades, also called moving blades, are blades that rotate at high speed with the rotor. The high-speed rotation of the blades realizes the energy conversion between the airflow and the rotor. The rotor blades bear large mass inertial forces, large aerodynamic forces, and vibration loads, and also withstand the corrosion and oxidation of environmental media, as well as the erosion of small particles running at high speeds. However, processing is difficult, and turbine rotor blades must be processed at high temperatures. Work in condition. The rotor blade is a key part that directly affects the performance, reliability, and life of the engine. Its working conditions are very harsh and easy to be damaged. Therefore, the requirements for material performance have also been greatly improved. At the same time, the economic cost of the material has been increased, and repair tapes have also been used for it. Come to the vast market. The application of laser cladding technology on rotor blades has been well studied, which also provides a favorable prerequisite for its application in repair.
Usually, the main causes of failure of shaft parts include shaft deformation, shaft fracture, and shaft surface failure. Research shows that the damage to shaft parts such as generator shafts and various transmission shafts is mainly caused by wear. Among them, shaft deformation and shaft fracture cannot be repaired, but surface failure mainly caused by wear can be repaired. Using high-power laser cladding repair technology, a layer of iron-based alloy material can be laser cladding on the failed surface of shaft parts, so that the surface of the parts with the cladding alloy layer has good mechanical properties, and the scrapped parts can be reused.
Mold plays an important role in casting molding and plastic molding processing. Its manufacturing process is complex, the production cycle is long, and the processing cost is high. Therefore, repairing and reusing failed molds undoubtedly has significant economic benefits. The service life of the mold depends on its ability to resist wear and mechanical damage. Once excessive wear or mechanical damage occurs, it must be repaired before it can be used again. Laser cladding has become a research hotspot for repairing molds and has attracted much attention from domestic and foreign scholars.
The method of laser cladding to repair the surface wear of the mold can be summarized as follows: using a high-power laser beam with a constant power P and a hot powder flow to be incident on the mold surface at the same time, part of the incident light is reflected, part of the light is absorbed and is instantly After the absorbed energy exceeds a critical value, the metal melts to create a molten pool, which then solidifies rapidly to form a metallurgically bonded cladding. The laser beam scans back and forth to repair the mold line by line and layer by layer according to the route given by the CAD secondary development application. In particular, the repaired mold requires almost no reprocessing.
