Precision casting technology development and applications of silica sol embodiment

Precision casting technology development and applications of silica sol embodiment
The current world developed country of the industry on the precision casting technology development goals there are roughly four, specific for the:
(1) The improvement of casting quality and reliability, the production of high quality near net shape casting;
(2) Short delivery;
(3) Protect environment, decrease or eliminate pollution;
(4) Reduce production cost.
Silica sol used in investment casting is mainly reflected in the following three aspects, in order to:
First : the sol is mainly used for precision casting coating binder, used as a shell of the surface coating and a reinforcement layer coating. The small particles of silica sols used in precision casting, instead of ethyl silicate, not only can reduce the cost, but also can improve labor conditions. For shell precision casting, can make the shell type high strength, high size precision, casting good smoothness, styling than water glass of good quality, inexpensive and ratio of ethyl silicate. Large castings, high surface finish casting and requires no margin or less allowance is particularly suitable for casting. The silica sol is used as a mold resistant coating, the coating has excellent heat resistance, wear resistance, can reduce the high temperature molten metal mold loss, and helps to release.
Second: investment casting process, that is simple with the fusible material fusible model, in which several layers of refractory coating special coating, after drying and hardening to form a whole body shell, and then the steam or hot water from shell model of melt, and then the shell in the sand box, in the around the filling of dry sand molding, finally will be cast into the furnace through high temperature roasting, mold or mold shell after roasting, in which a molten metal pouring and casting.
Third: pressing mold, using the cavity surface smoothness high pressure, therefore, casting surface finish is relatively high. In addition, the shell is made of high temperature resistant special binder and refractory material compounding refractory coating on casting made direct contact with molten metal, the cavity of high surface smoothness.