Effect of wall thickness of aluminum alloy castings on solidification rate

In the process of pressure casting, the wall thickness of die casting is a factor with special significance. Wall thickness is closely related to the whole process specification, such as the calculation of filling time, the selection of gate speed, the calculation of solidification time, the analysis of mold temperature gradient, the role of pressure, the length of mold residence time and so on.

Casting ejection temperature and operating efficiency; The wall thickness of parts will obviously reduce the mechanical properties of die castings, and the thin-walled castings have good compactness, which relatively improves the strength and pressure resistance of castings. Gradually, the wall thickness should not be too thin, which will lead to defects such as poor filling of aluminum liquid, difficult molding, poor welding of aluminum alloy and cold insulation of casting surface, which will bring difficulties to die casting process. With the increase of wall thickness, the defects such as porosity and shrinkage cavity in die casting increase. Therefore, on the premise of ensuring sufficient strength and rigidity of the casting, the wall thickness of the casting should be as thin as possible and the section thickness should be uniform. In order to avoid shrinkage porosity and other defects, the back wall of the casting should be thinned and ribs should be added. For large-area flat thick-walled castings, ribs are set to reduce the wall thickness of the castings; According to the surface area of die casting, the reasonable wall thickness of aluminum alloy die casting is: surface area of die casting /mm ㎡ wall thickness s/mm ≤ 25.10-3.0 > 25-1001.5-4.5 >100-400.