After adequate dry thickness, together with temperature, so that internal melting wax off, get in line the cavity with the required precision casting blank is compared with the traditional casting process in terms of a casting method can be relatively accurately shape and high casting made the production of precision casting process: first, to make the necessary rough electrode, second electrode corruption model specific, forming the third cavity, with casting wax casting method to obtain the original model in wax on wax Brush layers of sand on the high temperature of the liquid material and finally cast in the mold cavity in molten iron, the shell removed after curing can be finished with high precision.
China is in the last century, the fifties and sixties began casting for industrial production. This advanced casting process was a tremendous development, one after another in the aerospace, automotive, machine tools, ships, internal combustion engines, gas turbine, telecommunications equipment, weapons, Manufacture of medical equipment and cutting tools are widely used in industry, but also for arts and crafts manufacturing.
The so-called investment casting process, it simply is to use fusible material can melt model, in its coated with some special fire-resistant coating layer, after drying and hardening after the formation of a whole shell, and then steam or hot water from the Shell in the melting of the model, then Place the shell in the sand box, fill in the surrounding dry sand molding, and finally cast into the roaster in the high temperature roasting, shell mold or by calcination in which pouring molten metal and get casting.
High dimensional accuracy of castings, generally up to CT4-6, of course, the process as the process of casting complex factors that affect the size precision casting more materials such as mold shrinkage, melting mode of deformation, and shell in the heat amount of cooling change the course of the line alloy solidification shrinkage and deformation of the casting process, so the size of ordinary investment castings precision are higher, but still need to improve their consistency.
Suppression of melting mode, the cavity surface finish using high-pressure type, therefore, melting mold surface finish is relatively high. In addition, a special shell from the high temperature binder and refractory material made into a fire-resistant paint coating on the wax pattern hanging made with molten gold cavity is in direct contact with high surface finish.
Melt casting the biggest advantages is because the TIG Casting has very high precision, surface finish Do not be worried mechanical processing work, Zhi Shi in part on the requirements of the site to stay a little higher allowances can be, and even some of the casting Zhi stay grinding, Polishing margin, can be used without machining. This shows that the use of investment casting method can save a lot of machine tool equipment and processing time, a substantial savings of metal materials.
Another casting method of the advantages is that it can cast a variety of complex alloy castings, in particular, can be made into high-temperature alloy castings. Such as jet engine blades, its sleek profile and cooling outside the cavity, with the machining process is almost impossible to form into. With the production of investment casting process can be done not only to mass production, ensures consistency of the casting and machining to avoid the knife after the pattern of residual stress concentration.