The role of air holes in the fully automatic film covered sand shell production line

The fully automatic film coated sand shell production line is subjected to the thermal and chemical effects of the molten steel during the pouring process, causing the resin and other gas substances to evaporate, decompose, and burn, producing a large amount of gas. Therefore, the size of the gas generation directly affects whether the casting has porosity defects. The pores generated by coated sand castings are generally invasive and reactive pores, among which the invasive pores are more common, while the reactive pores are less common.

During the pouring process, the characteristics of the pores are basically the same, forming a spherical shape, a ball shape, and sometimes a pear shape. The direction pointed by the small end of the pear shaped pores is the direction of the airflow, that is, the location of the external pore source; The surface of the pore wall is smooth and the size is relatively large, usually internal pores, often located in the upper mold during casting. Sometimes surface pores are formed on the surface of the casting, or subcutaneous pores are formed under the skin, and most of the time they are single or clustered larger sized pores.