Cast impeller material and casting defects

The material of a cast impeller is aluminum silicon alloy zalsi9cu2mg. The cast impeller is not allowed to have casting defects such as crack, air hole, sand hole, shrinkage porosity and shrinkage cavity in actual production. According to the national standard GB / T 1173-1995, its chemical composition is shown in the table.

As shown in the figure, it is a 3D physical drawing of the cast impeller. The maximum dimension is 920mm, the average wall thickness is 7mm, the wall thickness of the upper and lower parts in contact with the blade and the blade is uniform, and the small wall thickness is 6mm at the blade of the cast impeller; The matching part between the middle and the rotary shaft is the part with the largest wall thickness, with the maximum wall thickness of 90mm, the maximum hole diameter of 580mm and the minimum hole diameter of 110mm; Because the casting impeller is a medium-sized casting and the pouring temperature is relatively low, it is easy to produce defects such as insufficient pouring, shrinkage cavity, shrinkage porosity and deformation in the process of pouring and solidification.

According to the structure and manufacturability of the cast impeller and the need for mass production of a single piece, it is comprehensively considered to select furan resin sand for mechanical molding and core making through hot core box. In this way, the dimensional accuracy of the cast impeller is relatively high, its processing surface is smooth and the production efficiency is high.