As an advanced production technology, silica sol precision casting has not been developed for a long time in China, but it has developed very fast in recent years and its development prospects are also very good. Silica sol precision casting products have relatively high precision requirements in the production process. Silica sol precision casting needs to strengthen the understanding of product technology in theory and practice, and continue to supplement its professional knowledge.
Silica sol precision casting has enriched its practical experience. In the process of use, the entire silica sol precision casting production process will be straightened out to cast more powerful quality products. During the filling process, the foam model needs to be decomposed by liquefaction. A lot of small molecule gas and foam ash will be produced.
These substances are harmful to people to a certain extent. In daily work, operators must strictly follow their operation manuals. Whether it is actual operation or auxiliary protection items, they must be carried out according to their needs. During the production process Need to be proficient in the operation steps.
Silica sol precision casting For some complex thin-walled castings, in order to effectively improve the air permeability of the molding shell of the precision castings during the use process, if possible, vent holes can be set at a higher position. This is a reasonable setting The pouring system prevents pouring gas.
In the process of using silica sol precision casting, the pouring temperature is appropriately increased, and the distance between the ladle nozzle and the pouring cup is minimized, and the pouring speed is effectively reduced, so that the molten metal can be filled smoothly.
The mold shell of silica sol precision casting must be fully baked, and the temperature must be high enough during use, so as to ensure that the precision casting shell is completely baked, so that the product's gas-producing substances are fully eliminated, and the completely baked mold shell is white or light. Gray, there should be no dark spots.
Application of Silica Sol Technology in Precision Casting
1. The silica sol process is called investment casting, which is a casting process with little or no cutting. It is an excellent process technology in the foundry industry. It is also called silica sol precision casting and has a wide range of applications. It is not only suitable for casting of various types and alloys, but also produces castings with higher dimensional accuracy and surface quality than other casting methods, and even complex, high-temperature resistant, and difficult-to-process castings that are difficult to cast by other casting methods. Can be cast by investment casting.
2. Investment casting is developed on the basis of ancient wax casting. As an ancient civilization, China is one of the earliest countries that used this technology. As far back as hundreds of BC, the ancient working people in China created this lost wax casting technology, which was used to cast various fine patterns and characters. Zhong Ding and utensils, such as the tomb of Zeng Hou Yi in the Spring and Autumn Period. The base of the tomb of Zenghouyi’s tomb is composed of multiple intertwined dragons. They are connected end to end and staggered up and down to form a hollowed-out multilayer moiré-like pattern. These patterns are difficult to produce by ordinary casting techniques, but are cast by lost wax The craftsmanship can take advantage of paraffin wax’s lack of strength and ease of engraving. Common tools can be used to engrave crafts made of paraffin wax that are the same as the tomb of Zenghou Yi’s tomb, and then a pouring system, coating, dewaxing, and pouring can be added. You can get the exquisite tomb of Zeng Hou Yi.
3. The practical application of modern investment casting methods in industrial production was in the 1940s. The development of aviation jet engines at that time required the manufacture of heat-resistant alloy parts such as blades, impellers, nozzles, etc., with complex shapes, precise dimensions, and smooth surfaces. Because heat-resistant alloy materials are difficult to machine and the shapes of parts are complex, it is impossible or difficult to manufacture by other methods. Therefore, it is necessary to find a new precision molding process, so the lost wax casting handed down in ancient times is used for reference. The modern investment casting method has obtained important development on the basis of ancient craftsmanship. Therefore, the development of the aviation industry has promoted the application of investment casting, and the continuous improvement and perfection of investment casting has also created favorable conditions for the aviation industry to further improve its performance.
Silica sol precision casting will effectively enable its hydraulic metal to better fill the cavity, copy the shape of the cavity, and improve the accuracy of the casting to prevent the defects of porosity and insufficient pouring.
Silica sol crystallizes under the pressure of precision casting. When it is used, its shell is effectively placed in the pressure tank for casting. After the product is finished, the pressure tank will be immediately closed, and it will be introduced into the tank during use. High pressure air or inert gas solidifies the casting under pressure to increase the density of the casting.
If silica sol precision casting adopts its thermal gravity casting, this is a more widely used form of casting during use. After the shell is taken out of the baking furnace, it is poured at high temperature.
The directional crystallization of silica sol precision casting. When in use, some investment castings such as magnetic steel and turbine blades, etc., if their crystalline structure is columnar crystals arranged in a certain direction, their working performance can be improved a lot, so investment castings Casting oriented crystallization technology is developing rapidly.