In the use of induction melting furnace in the investment casting, wax loss method is a very common method, wax loss method is now called investment casting, is a kind of less cutting or no cutting of the investment casting process, is an excellent process technology in the investment casting industry, its application is very wide. It is not only suitable for the investment casting of various types and alloys, but also produces castings with higher dimensional accuracy and surface quality than other investment casting methods. Even the complex, high temperature resistant and difficult to process castings which are difficult to be cast by other investment casting methods can be cast by investment casting.

Investment casting is developed on the basis of ancient wax casting. As an ancient civilization country, China is one of the earliest countries to use this technology. As far back as several hundred years BC, the ancient working people of our country created this lost wax precision casting technology, which was used for precision casting products such as bells, tripods and utensils with various fine patterns and characters, such as the zunpan in the tomb of Marquis Yi of Zeng in spring and autumn. The base of the zunpan in the tomb of Marquis Yi of Zeng is made up of several intertwined dragons, which are connected end to end and interlaced up and down to form a multi-layer moire pattern with hollow out in the middle. These patterns are difficult to be made by ordinary precision casting process. However, by using the lost wax method, we can make use of the characteristics of paraffin wax that has no strength and is easy to carve, and use ordinary tools to carve the desired Marquis Yi of Zeng The exquisite tomb Zun pan of Marquis Yi of Zeng can be obtained by adding a pouring system, coating, dewaxing and pouring.

It was in 1940s that modern investment casting method was applied in industrial production. At that time, the development of Aerojet engine required the manufacture of heat-resistant alloy parts with complex shape, accurate size and smooth surface, such as blades, impellers and nozzles. Because heat resistant alloy materials are difficult to machine and the shape of parts is complex, it is impossible or difficult to manufacture by other methods. Therefore, it is necessary to find a new precision molding process. By learning from the lost wax precision casting handed down from ancient times, through the improvement of materials and technology, modern investment casting method has obtained important development on the basis of ancient technology. Therefore, the development of aviation industry promotes the application of investment casting, and the continuous improvement and perfection of investment casting also creates favorable conditions for further improving the performance of aviation industry.

Investment casting has been used in industrial production since 1950s and 1960s in China. Since then, this advanced precision casting technology has been greatly developed, and has been widely used in aviation, automobile, machine tool, ship, internal combustion engine, gas turbine, telecommunication equipment, weapons, medical equipment, cutting tools and other manufacturing industries, as well as in the manufacturing of Arts and crafts.

The so-called investment casting process, simply speaking, is to use fusible materials (such as wax or plastic) to make a fusible model (investment model or model for short), coat it with a number of layers of special refractory coating, after drying and hardening to form a whole shell, then use steam or hot water to melt the model from the shell, and then put the shell in the sand box, and fill the dry sand around it to make the mold Finally, the mold is put into the baking furnace and roasted at high temperature (for example, when the high strength shell is used, the demoulded shell can be roasted directly without molding). After the mold or shell is roasted, the metal melted in the induction furnace is poured into it to obtain the casting.

The dimensional accuracy of investment castings is high, generally up to ct4-6 (ct10-13 for sand casting and ct5-7 for die casting), Of course, due to the complex process of investment casting, there are many factors affecting the dimensional accuracy of castings, such as shrinkage of mold material, deformation of investment mold, linear variation of shell during heating and cooling, shrinkage of alloy and deformation of castings during solidification, etc The dimensional consistency of high temperature wax casting should be improved a lot.

When pressing the investment mold, the mold with high cavity surface finish is used, so the surface finish of the investment mold is also relatively high. In addition, the shell is made of refractory coating made of high temperature resistant special binder and refractory materials, which is coated on the investment mold. The surface finish of the cavity directly contacting with the molten metal is high. Therefore, the surface finish of investment castings is higher than that of ordinary investment castings, generally up to ra.1.6 ~ 3.2 & mu; M.

The biggest advantage of investment casting is that because investment casting has high dimensional accuracy and surface finish, it can reduce the machining work, just leave a little machining allowance in the parts with high requirements, and even some castings only leave grinding and polishing allowance, which can be used without machining. It can be seen that the investment casting method can save a lot of machine tools, processing time and metal raw materials.

Another advantage of investment casting is that it can be used to cast complex castings of various alloys, especially superalloy castings. For example, the blade of jet engine can hardly be formed by machining. Investment casting process can not only achieve mass production, ensure the consistency of castings, but also avoid the stress concentration of residual knife marks after machining.

Yiphee Electric Furnace Co.,Ltd specializes in producing induction furnace.Tel(WhatsApp):+86-13450756789, yiphee@yiphee.cn