Effect Of Coating's Wetting Ability For Liquid Polystyrene On Casting Defects

In this thesis we discuss the developing and studying statement of coating, which is key technology of lost foam casting, aimed at the carbon defects existing in iron casting and steel casting, probe into the formulation mechanism of the carbon defects by analyzing the polystyrene's gasification and decomposition process, we believe that if the polystyrene foam totally discharging the coating layer in the form of gaseous state, that will inevitable produce a large number of carbon which is held up in type and cause the formation of the castings' carbon defects. We have put forward the coating wetting ability concept to the liquid polystyrene, and there are direct relations between the carbon defects of casting and the wetting ability of coating layer to liquid polystyrene. We have carried on a series of test on the coating layer's ventilative, wetting and pouring, through analyzing the result of the test, we found that if the coating layer has a high wetting ability to liquid polystyrene, then the liquid polystyrene can majority discharge through the coating layer by liquid form, which can purify the type, improve the filling ability, and reduce the carbon defect of the casting effectively. The contrast under the real working condition is poured and tested, has verified the performance in practical application of coating that a subject compounds out. Through analyzing the electric mirror photo of scanning the coating layer, we observe the micro shape of the coating layer and compare, verify the wetting ability theory of the coating.