Once the processing of gray iron castings causes looseness and shrinkage, it becomes waste material. Looseness may first be caused by unscientific construction. Loosening, shrinkage, and shrinkage are caused on areas with large wall thickness, Even at the concave corner, due to the fact that the heat is discharged based on the corresponding mold convex part or clay core, the heat discharge at this point is poor, and the metal material solidifies relatively slowly. The experimental results show that the external shrinkage at the concave corner of Y-shaped concrete specimens with 30 °, 60 °, or 90 ° tension angles decreases with the expansion of the tension angle, and in addition, the shrinkage decreases, leading to an increase in looseness.

　　One of the key standards for obtaining high-density castings is the effective construction of the design scheme and processing technology. But for a casting; When constructing the designer's design plan, the first consideration is the application regulations; The second is the rationalization of processing technology.