Silica sol process stainless steel casting belongs to investment precision casting or precision casting. It is a casting process with little or no cutting, and is an excellent process technology in the foundry industry. Chinese name stainless steel casting belongs to investment casting or precision casting, and its application is very wide, suitable for casting of various types and alloys

Stainless steel casting 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 cast castings that are difficult to cast by other casting methods. The processed castings can be cast by investment casting.

The so-called investment casting process, simply put, is to use fusible materials (such as wax or plastic) to make a fusible model (referred to as investment mold or model), and apply several layers of special refractory coatings on it. After drying and hardening to form an integral shell, steam or hot water is used to melt the mold from the shell, then the shell is placed in a sand box, filled with dry sand molding around it, and finally the mold is placed in a roaster After high temperature roasting (for example, when high-strength mold shell is used, the mold shell after demolding can be directly fired without molding), after the casting mold or mold shell is fired, molten metal is poured into it to obtain castings.

The dimensional accuracy of investment castings is relatively high, generally reaching 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 that affect the dimensional accuracy of castings , such as the shrinkage of the mold material, the deformation of the investment mold, the linear change of the shell during heating and cooling, the shrinkage rate of the alloy, and the deformation of the casting during the solidification process, so the dimensional accuracy of ordinary investment castings is higher. , but its consistency still needs to be improved (the dimensional consistency of castings using medium and high temperature waxes is much improved).

When pressing the investment mold, the mold with high surface finish of the cavity is used, so the surface finish of the investment mold is also relatively high. In addition, the shell is made of high temperature-resistant special binder and refractory paint prepared from refractory materials, which is coated and hung on the investment mold, and the inner surface of the cavity that is in direct contact with the molten metal has a high smoothness. Therefore, the surface finish of investment castings is higher than that of general castings, generally reaching Ra.1.6~3.2μm.

The biggest advantage of investment casting is that investment castings have high dimensional accuracy and surface finish, so machining work can be reduced, just leave a little machining allowance on parts with higher requirements, even some Some castings only have grinding and polishing allowances, and can be used without machining. It can be seen that the use of investment casting method can save a lot of machine tool equipment and processing time, and greatly save metal raw materials.

Another advantage of the investment casting method is that it can cast complex castings of various alloys, especially superalloy castings. For example, the blade of a jet engine has a streamlined outline and an inner cavity for cooling, which can hardly be formed by machining. The investment casting process can not only achieve mass production and ensure the consistency of castings, but also avoid the stress concentration of residual knife lines after machining.