Among the more commonly used is the investment casting, also known as the lost wax casting: choose appropriate casting material (such as paraffin) manufacturing investment;Touch on casting refractory coating and sand and refractory process, sclerosis type shell and dry;Then the internal casting melt away, get the cavity;Roasting shell in order to obtain enough strength, and the casting material, burning residual;Casting need metal materials;After shelling solidification cooling, deoxidization, can achieve the high precision finished products.According to the requirements of the product or heat treatment and cold working and surface treatment.Being carried out by the several iron and steel research institute of TiAl alloy revestment precision casting, is preliminary already produce vehicles with pressurization turbine engine and the exhaust valve and nozzle jet engine parts, at present its technical level is in the stage of laboratory research.