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  • Dongying Fuhao analyzes the advantages of investment casting

    Issuing time:2018-11-16 16:03

    The so-called investment casting process, simply by making a fusible model with a fusible material, is coated with several layers of special refractory coatings. After drying and hardening to form a monolithic shell, steam or heat is used. Water melts the model from the shell, then places the shell in the sand box, fills the dry sand shape around it, and finally puts the mold into the roaster and then roasts it at high temperature (if using a high-strength shell, it is not necessary) The mold is directly fired after demolding, and after the mold or the shell is fired, molten metal is poured therein to obtain a casting.


    Investment castings have high dimensional accuracy, generally up to CT4-6 (sand casting is CT10~13, die casting is CT5~7). Of course, due to the complicated process of investment casting, there are many factors affecting the dimensional accuracy of castings, such as mold. The shrinkage of the material, the deformation of the investment mold, the change in the amount of the shell during heating and cooling, the shrinkage of the alloy, and the deformation of the casting during solidification, etc., so the dimensional accuracy of ordinary investment castings is high, but Consistency still needs to be improved (the dimensional uniformity of castings using medium and high temperature waxes is much higher).


    When the investment mold is pressed, the molding having a high surface finish of the cavity is used, and therefore, the surface finish of the investment mold is also relatively high. In addition, the shell is made of a refractory paint made of a special binder and a refractory material which is resistant to high temperature, and is coated on the investment mold, and the inner surface of the cavity which is in direct contact with the molten metal has a high surface finish. Therefore, the surface finish of the investment casting is higher than that of the general casting, and generally reaches Ra.1.6~3.2μm.


    The biggest advantage of investment casting is that because of the high dimensional accuracy and surface finish of the investment casting, the machining work can be reduced, but only a small amount of machining allowance is required on the parts, even some castings only The grinding and polishing allowance can be used without machining. It can be seen that the investment casting method can save a lot of machine tool equipment and processing man-hours, and greatly save metal raw materials.


    Another advantage of the investment casting process is that it can cast complex castings of various alloys, particularly casting high temperature alloy castings. For example, the blade of a jet engine, the streamlined profile and the cooling cavity, can hardly be formed by a machining process. The production by the investment casting process can not only achieve mass production, but also ensure the consistency of the castings, and avoid the stress concentration of the residual knives after machining.

    ?2018copyright Dongying Fuhao Precision Casting Technology Co., Ltd.