Silica sol casting has the advantages of high dimensional accuracy and good surface quality. It is a widely used advanced process with less and no cutting. Using silica sol casting method can not only save a lot of machine tools and processing hours, but also greatly save metal raw materials. Silica sol casting is a widely used precision casting method in the field of precision casting. This precision casting method effectively reduces the cost and improves the competitiveness of precision casting enterprises. Casting is the most important step in silica sol casting. What are the common casting methods of silica sol casting?
1. Crystallize under pressure. Place the mold shell in the pressure tank for pouring. After that, immediately close the pressure tank and inject high-pressure air or inert gas into the tank to solidify the casting under pressure, so as to increase the density of the casting.
2. Vacuum suction pouring: put the mold shell in the vacuum pouring box and suck the gas in the mold cavity through the small pores in the mold shell, so that the liquid metal can better fill the mold cavity, copy the shape of the mold cavity, improve the casting accuracy and prevent the defects of insufficient pores and pouring. This method is more common abroad.
3. Directional crystallization. Some investment castings, such as turbine blades and magnetic steel, can improve their working performance if their crystalline structure is columnar crystals arranged in a certain direction. Therefore, the directional crystallization technology of investment casting is developing rapidly.
4. Thermal gravity pouring, which is the most widely used pouring form, that is, after the shell is taken out of the roasting furnace, pouring is carried out at high temperature