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Low pressure casting is a very excellent casting process. With the continuous development, it has realized mechanized and automatic production, which is of great significance to improve production efficiency and yield. However, this technology is not ideal for all parts casting, such as wheel hub casting, which will produce different defects due to various factors.

The common defect of low pressure casting wheel hub is the generation of cracks, especially in the stress concentration position, cold crack and hot crack are two very common phenomena. When the casting is cooled to a low temperature, the casting stress acting on the casting will exceed the strength or plasticity of the casting itself, thus promoting the generation of cracks. During the solidification process, due to the heat transfer of the mold wall, the casting will solidify from the surface and appear solid shrinkage. At this time, when the shrinkage of dendrite layer is hindered, the dendrites will be pulled apart and hot cracks will appear.

In addition to process factors, the structure design, process parameters and mold temperature of the wheel hub will also cause such problems, so the improvement of casting technology can not be solved completely. It is necessary to improve the design of wheel hub structure, improve the mold problem properly, and ensure the casting molding of workpiece through reasonable liquid lifting system.