Grain Size of the Coated Sand
Compared with other resin bonded sand samples, within the commonly used particle size range for casting, the coated sand of Fused ceramic sand changes from large to small with the particle size of the original sand. Under the condition that the amount of resin is unchanged, the strength of the coated sand changes from high to low, the air permeability also decreases correspondingly, and the surface quality of the produced core and casting is improved accordingly.
At present, 50/100, 70/140, 100/200 coated sand is widely used in China, which mainly depends on the shape of the sand core, the application occasions, the requirements of castings, etc. Fused ceramic sand shell mold precision casting process is used to partly replace the original wax loss precision casting process or improve the accuracy and surface quality of the original ordinary sand mold casting. Generally, 100/200 mesh or finer raw sand is used. The principle of "five sieves are reasonably distributed and three sieves are relatively concentrated" is generally required. As a new type of artificial sand, fused ceramic sand has very different screening methods and physical and chemical properties from silica sand. Different particle size distribution can be configured according to needs. Some manufacturers have used coarser grain size and fine powder (140 mesh and below) as coated sand to produce high-quality castings. Fused ceramic sand manufacturers and foundries should cooperate more closely to explore and test coated sand with more particle size combinations.
About Resin Addition
Because the particle shape of fused ceramic sand is nearly spherical, and the general angle coefficient is <1.05, under the same strength requirements, the amount of resin added can be reduced by about 30% compared with that of quartz sand. According to the research, fused ceramic sand can significantly improve the performance of coated sand. For some small castings with not very complex structure, it mainly bears pressure and a small amount of shear force, does not need too high strength, and can reduce the gas evolution. Generally, the amount of resin addition is 1 ~ 1.8%.
Fused Ceramic Sand Play an Important Role in Shell Molding Process
1. Fused ceramic sand shell mold precision casting process can be widely applied to small and medium-sized castings with different materials such as cast iron, cast carbon steel, cast medium and low alloy steel, stainless steel and non-ferrous alloy
2. Using the Fused ceramic sand shell mold precision casting process, the casting dimensional accuracy can reach CT7 ~ CT6 grade, and the surface roughness can reach Ra125Up. It can greatly improve the quality of sand casting and partly replace the lost wax precision casting process.
3. The production efficiency and market reaction speed can be greatly improved by using Fused ceramic sand shell mold precision casting process.
4. The use of Fused ceramic sand shell mold precision casting process can significantly reduce the casting cost and achieve huge economic benefits
5. Fused ceramic sand shell mold precision casting process is simple and convenient to regenerate used sand, greatly reducing the discharge of pollutants such as solid waste. It has obvious environmental protection benefits while obtaining economic benefits. It is a sustainable casting technology.
6. Fused ceramic sand shell mold precision casting process will become a hot spot of new practical casting technology for a considerable period in the future.