The quality status of castings after sand dropping and shot blasting in the two sand mold casting process tests is similar, as shown in Figure 1. The surface roughness of sand mold casting is good, the size meets the tolerance requirements of the drawing, there is no sand sticking, and the outer surface is free of naked eye cracks, pores and other defects. However, there are open cracks at the root of the riser, with a depth of about 10mm, and there are many sand inclusions on the rough surface of sand mold casting.
The collapse of sand mold is shown in Figure 2 and 3. The sand mold in direct contact with the sand mold casting has good collapsibility due to the high temperature of the sand mold casting and full combustion of the sand mold; The sand mold not in contact with the casting in the sand box has secondary solidification due to heating, and the molding sand strength becomes very high, but it is not fully burned and is difficult to break, which increases the cleaning cost of the sand box and the difficulty of sand regeneration.
