Main characteristics of investment casting

Today Wuxi Kaihan Technology Co., Ltd. will introduce investment casting. Investment casting is to use fusible materials to make an accurate mold. On the mold, a multi-layer mold shell composed of refractory materials and high-strength adhesives is formed by coating. After the mold shell is hardened, it is heated to lose the mold, and then the mold shell is baked at high temperature to cast alloy to obtain castings. As wax stearic acid pattern material is widely used in fusible mold, it is also called lost wax casting.

Investment casting has a long history in China. As early as the Shang Dynasty, our ancestors used a similar method to cast highly artistic Zhongding and vessels, which were exquisite in shape and exquisite in workmanship. It was recorded in the Dongtian Qinglu Collection written by Zhao Xigu of the Song Dynasty and Tiangong Kaiwu written by Song Yingli of the Ming Dynasty. In recent decades, due to the development of industry, science and technology, and with the continuous improvement of casting quality requirements, investment casting has been widely used.

Primary characteristics of investment casting

1. Investment casting has no parting surface, so it can produce castings with disordered shapes. It can complete the manufacturing of disordered components originally composed of multiple parts, simplify the structure, save labor hours and materials.

2. Investment casting has high dimensional accuracy and good appearance quality, which belongs to precision casting.

3. Investment casting alloy is not limited. It is used for high melting point and hard cutting alloy, which shows its remarkable advantages.

Investment casting process is complex, production cycle is long, raw materials are expensive, and production costs are high. In addition, due to the limit of wax pattern strength, the castings should not be too large or too long, generally less than 25kg.

Now investment casting is mainly used for the production of steam turbine, gas turbine, pump blades, miscellaneous instrument components, cutting tools, and various weapons, electric and pneumatic tools and other parts. In recent years, investment casting has developed processes such as outward grain refinement, vacuum directional casting and single crystal blade casting, which have greatly improved the heat resistance and fatigue strength of high-speed blades and extended their service life.

As far as investment casting is concerned, the castings are not large. When the castings are shot blasted mechanically, the more the equivalent of steel shot, the better. From the operation condition of the shot blasting machine, the incidence angles of the steel shot of the crawler type shot blasting machine are the same, and the steel shot of the hook type shot blasting machine are two opposite incidence angles. How can the shell and oxide skin on the surface of the casting be completely removed without multi-directional incidence angle. First, the castings in the bucket are rolling and rolling constantly, transposing the direction not hit by the castings to the shot peening range of the incidence angle; Second, the steel shot is thrown out at a high speed through the shot blasting machine. Due to the principle of acceleration and inertia, the steel shot thrown out of the direct shot has a very large impact force to hit the casting. The steel shot bounces back to hit each other by castings with similar hardness, bounces back to the inner wall of the bucket, and then bounces back to the casting by the inner wall. Under the three kinds of external ejection twin fruits, the steel shot is constantly hit each other, so it is transformed into a different angle to hit the appearance of the casting.

The above is what Wuxi Bill Technology Co., Ltd. introduced to us.