Domestic paints for lost foam casting

Actual technological task in lost foam casting (LFC) is preventing metal penetration appearance on the steel and cast-iron mouldings. In the result of the research appropriate parting model paint compositions are developed with the use of recycling and nanostructured materials. They include not only “traditional” extenders (starch (viscosifier), bentonite (stabilisator), technical lignosulfonates (bonding and surface-active material), penetrant OP-7) but also the following progressive materials. For steel LFC: aqueous solutions of alumina-boric-phosphate concentrate, powdered periclase, nanostructured diamond powder, white electrocorundum. For cast-iron LFC: the above-mentioned materials, but instead of the expensive electrocorundum a reversal bath of electrode production is used. The basic technological characteristics of the developed parting model paint compositions are: relative stickiness due to VZ-6: 18...25 s; residual moisture content 1...1.5 %, permeability to gases 40...50 ea. For sensitive castings it is supposed to involve bubble ultrasonic machining of coating suspension. Exposure to ultrasonic field in the process of coating composition preparing activate alumina-boric-phosphate bonding, rise its adhesion to minute surfaces of figurine polystyrene models. The use of bubbling together with ultrasonic processing of the coating composition provides major improvements in permeability to gases of the antipenetration wash. Parting paint effectiveness is determined by defect reduction of the castings on the core blow, uncertainty in geometry, metal penetration, and also the use of available and environmentally friendly molding materials in their composition, that makes the product to be highly competitive.