Precision Casting of Stainless Steel Casting Parts

Date:23-01-2018

Stainless Steel Casting Parts commonly used precision castings, also known as investment casting. The so-called investment casting process, simply put it is made of fusible material (such as wax or plastic) fusible model (referred to as the melt or model), coated with several layers of special fire-resistant coating, after drying and hardening After forming an integral shell, the model is then melted from the shell with steam or hot water, the shell is then placed in a sand box, filled with dry sand around, and finally the shell is placed in a roaster and subjected to high temperature Roasting (such as using high-strength shell, you can not model the shell after demolding directly roasting), mold or shell after firing, in which the molten metal casting castings obtained.

Investment casting size accuracy is high, generally up to CT4-6 (sand cast CT10 ~ 13, die-casting CT5 ~ 7), of course, due to the complexity of the investment casting process, casting dimensional accuracy factors, such as mold The shrinkage of the material, the deformation of the mold, the change of the line volume of the shell during heating and cooling, the shrinkage rate of the alloy and the deformation of the casting during the solidification process, etc. Although the dimensional accuracy of the ordinary investment casting is relatively high, Consistency still needs to be improved. (Consistency of castings with medium and high temperature waxes should be much improved.)

Molding press, the cavity surface finish with high pressure, therefore, the surface finish of the investment is relatively high. In addition, the shell is made of high temperature resistant special binder and refractory coating made of refractory coating coated on the melt made of the molten metal in direct contact with the cavity surface finish. Therefore, the investment casting surface finish than the average casting high, generally up to Ra.1.6 ~ 3.2μm.

The biggest advantage of investment casting is due to the investment casting has a high dimensional accuracy and surface finish, it can reduce the machining work, but the parts require higher parts to leave a little allowance, and even some of the castings only Leave grinding, polishing allowance, you can use without machining. Thus, the use of investment casting method can save a lot of machine tools and processing time, a substantial saving of metal raw materials.

Another advantage of the investment casting method is that it allows the casting of complex castings of various alloys, in particular of superalloy castings. Such as jet engine blades, its streamlined profile and the cooling cavity, using mechanical processing is almost impossible to form. With investment casting process can not only do mass production, to ensure the consistency of the casting, and to avoid residual machining after machining stress concentration.