Application of Cold Spraying Repair Machine in Defect Study of Castings
Abstract
Studies on casting defects and the application of cold spraying repair machine has been an important area of research. This paper presents an overview of the causes of casting defects and the advantages of cold spraying repair machine to repair those defects. Research results and application practices have been discussed. In addition, the further application and development trend of the cold spraying repair machine in the field of casting defect repair have been predicted.
Introduction
Castings involve molding and solidification in a special shape with molten metals, plastics or alloys for the purpose of obtaining parts with certain external shapes, sizes and internal structure. Castings are widely used in automotive, aerospace and other manufacturing industries. It plays an important role in ensuring normal operation and reliable performance. It is true that perfection of castings has been achieved through casting process innovation and optimization; however, in some cases, casting defects are unavoidable. Research on the cause of casting defects and methods of repairing them is important and needed. In modern times, the repair of casting defects has been revolutionized due to the emergence of cold spraying repair machine.
Analysis of causes of casting defects
The casting defect is a defect of metal or alloy liquid filling into the pre-prepared mold cavity. It is visible or invisible defects on the surface of the casting caused by metal or alloy liquid failure to fill the mold. These defects can have serious consequences on the performance and life of the casting and they should not be ignored. When casting defects occur, it is often necessary to analyze the causes of these defects. In general, the following are the more common causes of casting defects:
1. Impurities in the materials. Poor metallographic structure caused by improper proportioning of the alloy ingredients and oxidation, inclusion and other impurities in the material;
2. The size, shape and gap of the mold cavity will affect the flow of metal solution, so the size and gap of the mould should conform to the size drawing;
3. Excessive heating of the pouring system and metal solution will weaken the gasification of gas in the metal liquid and reduce the gas diffusion of the gas in the mold cavity, resulting in air bubbles in the casting and affecting the filling of the molten metal and alloy;
4. The heating of the furnace is too high or too low, and the molten metal or alloy cannot reach the optimum pouring temperature, resulting in poor filling of the mold cavity, resulting in a decrease in the quality of the casting;
5. Improper operation of core setting or inadequate inspection will also cause serious casting defects.
Application of cold spraying repair machine
Due to the advancement of modern technology and the development of the mechanical industry, cold spraying repair machines have been widely used in metallurgy, machinery and other industries to repair casting defects and welding defects. Cold spraying is a relatively new process and its application in casting defects repair is also making breakthroughs. Generally speaking, a cold spraying repair machine introduces particles through high pressure and impacts particles on the surface of defects so as to restore the product surface. It is an innovative technology to repair the defects in metallurgy and other industries, which has been widely applied in product manufacturing and maintenance.
1. Low processing cost. Particles of metal, ceramic, plastic and other materials can be used as cold spraying materials. The materials used are not only diversified, but also cheap, which can greatly reduce the cost of processing;
2. Range of application. Cold spraying repair machines are suitable for all kinds of engineering materials such as steel, copper, aluminum and ceramic. It can meet various requirements. In addition, the cold spraying repair machine is suitable for the repair of the edges, rims and surface defects of the materials;
3. Environmental protection. Cold spraying technology can greatly reduce the dust pollution during the repair process. The dust generated during the operation is only a few milligrams, which meets environmental protection requirements;
4. Easy to operate. Compared with traditional welding repair machine and other traditional repair techniques, the cold spraying repair machine is simpler and faster in operation, which reduces the labor intensity of the operator.
Discussion and development trend
In the actual process of repairing by cold spraying repair machine, due to the indistinct of process parameters, a certain surface layer defect defects are more likely to occur. In order to further reduce the defect rate, the process parameters of the cold spraying repair need further research, such as the appropriate current, pressure, rate and flux, in order to obtain the optimal parameters for the cold spraying repair.
In addition, in order to adapt to the needs of the higher performance of modern products and reduce the cost, the structure and temperature control system of the cold spraying repair machine should be further optimized, even better methods and materials should be used, such as ceramic particles, so as to improve the degree of reconstruction of the cold sprayed surface.
Conclusion
In summary, cold spraying technology is an important method for repairing casting defects and has been widely used in casting industry. Research shows that the cold spraying repair technique has advantages such as low cost, wide range of application, environmental protection, easy operation and so on, which has already played an important role in research, production and daily operation of casting industry. Despite the potential for further improvement in the application of cold spraying repair machines, it is expected that cold spraying repair machines will continue to lead the way in the design and use of defect repair technologies in the future.
