The pouring process of lost foam casting

The pouring process of lost foam casting is the process of molten steel filling and vaporization disappearing at the same time. The whole process needs to pay attention to: (1) The sprue should be filled with molten steel from beginning to end, if it is not satisfied, due to the limited strength of the coating layer, it is easy to cause sand collapse and air intake phenomenon, resulting in casting defects. (2) When pouring molten steel, we must grasp it to ensure that it is stable, accurate and fast. Instantly fill the gate cup and achieve a rapid and continuous flow, tons of molten steel in about a minute. If the molten steel of the casting in the same box is cut off, it will suck in the air, which may cause sand collapse or the problem of increasing porosity in the casting, resulting in the scrapping of the casting. (3) Lost foam casting adopts negative pressure closed type, and must be closed below the gate cup. The molten steel enters the molding mold, which begins to liquefy and burn, and vaporizes and disappears, and the front end of the molten steel forms a temporary cavity for a short distance, so the speed of designing the molten steel filling and the foam model disappearing at about the same speed. In order to prevent the molten steel from melting other models in the same box by high temperature radiation, the runner should be far away from the casting model. The position of the vertical runner is selected as the lowest position of the whole box casting. When pouring, pay attention to adjust and control the negative pressure vacuum degree within a certain range, after pouring, keep it in a certain negative pressure state for a certain period of time, the negative pressure stops, the molten steel condenses and comes out of the box.