Castin casting industry is a very common casting.
The process of silica solcasting is called precision casting and precision casting, is a less cutting or cutting casting process, casting industry is a high technology, its application is very wide. It is not only applicable to a variety of types, all kinds of alloy casting, and the casting dimension precision, surface quality than other casting methods must be high, and even other casting method is difficult to cast was complex, high temperature resistance, easy processing and casting, can be used in investment casting casting have.
The so-called investment casting process, that is simple with the fusible material ( such as wax or plastic ) made of fusible model ( referred to as the mold or model ), in which several layers of refractory coating special coating, after drying and hardened to form a monolithic shell, with steam or hot water from the shell in molten drop model, and then the shell in the sand box, around the filling of dry sand molding, finally will be cast into the furnace through high temperature roasting ( such as using high strength shell, can not form and will release after the shell direct roasting ), mold or mold shell after roasting, in which pouring the molten metal and casting.
investment casting dimension precision is higher, generally up to CT4-6 ( CT10~13 casting sand casting, CT5~7 ), as the investment casting process is complex, there are many factors affect the dimensional accuracy of castings, such as mold material, mold shrinkage deformation, shell in the process of heating and cooling the line variation, the shrinkage rate and the alloy in the solidification process of casting deformation, so the common casting dimension precision although higher, but still need to improve its consistency ( used in high temperature, wax casting dimension consistency to improve a lot ).
Pressing mold, using the cavity surface smoothness high pressure, therefore, casting surface finish is relatively high. In addition, the shell is made of high temperature resistant special binder and refractory material compounding refractory coating on casting made direct contact with molten metal, the cavity of high surface smoothness. Therefore, investment casting surface finish than the general casting high, generally up to Ra.1.6~3.2 μM.
investment casting is the biggest advantages for investment castings with high dimensional accuracy and surface finish, so can reduce the machining work, only in the higher parts of parts with machining allowance can be, and even some castings have only grinding, polishing cushion, without mechanical processing can be used. Thus, using investment casting method can save a lot of machine tool equipment and processing time, greatly saving metal materials.
method of other advantages, it can be all kinds of casting alloy complex castings, especially can cast superalloy castings. Such as a jet engine blade, the streamlined contour and cooling cavity, with mechanical processing technology can hardly form. Using investment casting production process not only can do mass production, ensuring casting consistency, but also avoids the machining residual knife profile of stress concentration.