Intruduction of Stainless steel castings

- Sep 13, 2018 -

    Stainless steel castings are the general name of cast steel parts produced with various stainless steel materials, mainly used in the corrosion conditions of various media.
     As early in 1910, it was found that when the Cr content in steel exceeded 12%, it had good corrosion resistance and oxidation resistance.Typical stainless steels contain one or more other alloying elements, such as Ni, Mo, Cu, Nb, Ti, in addition to Cr12%.
There are Cr stainless steel, Cr stainless steel and Ni stainless steel.The corrosion performance of stainless steel is mainly affected by carbon content and precipitated carbides. Therefore, the less carbon content of corrosion-resistant stainless steel, the better. Generally, carbon is no more than 0.08%.The stable carbide precipitated phase in the structure, so the content of C in heat resistant steel is higher, generally the carbon content is above 0.20%.

Widely used for food production equipment, chemical equipment, nuclear energy, etc
Precision instruments, petroleum equipment and other equipment also indispensable stainless steel figure.

Casting method:
Si-sol process stainless steel casting is a kind of casting process with less or no cutting. It is an excellent technology in the casting industry and is widely used.It is not only suitable for casting of various types and alloys, but also can be cast precisely by investment casting with higher dimensional accuracy and surface quality than other casting methods.
So-called investment casting process, simply be with fusible materials (such as wax material or plastic) into the meltability model (referred to as "investment pattern or model), on which the coated with several layers of tailor-made refractory coating, after drying and hardening type to form a whole shell, reoccupy steam or hot water from the melt in the shell model, and then put type shells in the sand, dry sand by filling in all round its modelling, finally will be cast into the furnace after high temperature roasting (such as high strength shell, can need not modelling and will release the shell directly after roasting), cast type or shell after roasting, and are casting in pouring molten metal.
Size precision investment castings, general of CT4-6 (sand casting is CT10 ~ 13, die-casting is CT5 ~ 7), of course, due to the complexity of investment casting process, factors influencing the dimension accuracy of castings is more, such as mold material shrinkage and deformation of casting, shell in the process of heating and cooling line quantity change, alloy of shrinkage and deformation of castings in the solidification process, so the average size although higher precision investment castings, but still need to improve the consistency (in medium and high temperature of the wax casting size consistency to improve a lot).
When pressing the mold, the mold is pressed with a high surface finish, so the surface finish of the mold is also relatively high.In addition, the mold shell is made of refractory coating made of high temperature resistant special binder and refractory material, which is hung on the melting mold.Therefore, surface smoothness of fused casting is higher than that of normal casting, generally reaching Ra.
The biggest advantage of investment casting is that due to the high dimensional accuracy and surface finish of investment casting, it can reduce the machining work, and only a little machining allowance can be left on parts with higher requirements, and even some castings can only be polished and polished, which can be used without mechanical processing.It can be seen that the method of investment casting can save a lot of machine tools and processing time and metal raw materials.
Another advantage of the investment casting method is that it can cast complex castings of various alloys, especially high-temperature castings.For example, the blade of a jet engine, its streamline profile and cooling cavity are almost impossible to form by mechanical processing.The production with investment casting process can not only achieve mass production, guarantee the consistency of the castings, but also avoid the stress concentration of the residual blade after machining.