The so-called investment casting process, simply with fusible material can melt model, in which a plurality of layers ofrefractory coating with special "coating, after drying and hardening to form a whole shell, and thensteam or hot water from the shell in the melt model, and then the shell into the sand box, dry sand filled in theround, finally willcast into the roasting furnace after high temperature calcination (such as the use of high-strength shell, need notother and direct baking shell after stripping), mold or mold shell roasting, the pouring of molten metal and casting.
Investment casting dimension precision is high, the general can reach CT4-6 (sand casting casting forCT10~13,CT5~7), as the process of investment casting of complex, there are many factors influencing the dimensional accuracy of castings, such as mold material, mold shrinkage deformation, shell in the heating and cooling process of the line changes, alloy during solidification shrinkage and deformation of casting, so the sizeaccuracy of commoncasting is higher, but still need to improve its consistency (the casting dimensionconsistency, high temperature waxto improve a lot).
Introduced.technology suppression, the pressure, cavity surface finish high therefore, casting surface finish is high.In addition, refractory coating "shell by special binder and refractory material with high temperature resistance is formulated as a target=" _blank "> coat hanging in the introduced.technology made, directcontact with the molten metal cavity surface finish high. Therefore, the investment casting surface finish than the general casting high,generally up to Ra.1.6~3.2 μ M
Investment casting the biggest advantage is due to the investment casting with high dimensional accuracy and surface finish, so can reduce mechanical processing work, just in the parts of the parts of the high demand fora little machining allowance can, even some casting only keep grinding, polishing allowance, need not mechanical processing can use. Therefore, the investment casting method can save a lot of machine tool equipment "target="_blank "> equipment and processing time, greatly saving metal material.
Investment casting method another advantage is, it can be all kinds of alloy casting complex casting, specialcastingsuperalloy castings. Such as jet engine blades, the streamline the profile and cooling chamber, with the machining process can hardly formation. With investment casting technology not only can do production batchproduction, and ensure the consistency of the casting, but also avoid the stress concentration of the residual knife lines after machining.
