Squeeze casting bucket teeth

Squeeze casting technology continuously applies pressure to the liquid metal in the forming process, which makes the liquid metal solidify rapidly and the grain refinement degree is better; Moreover, due to crystallization and solidification under pressure, the compactness of the product is high; There is no need to set a large pouring riser to feed, that is, the defects of shrinkage cavity and shrinkage porosity can be avoided; Because the sand mold and sand core are not used, the casting defects such as sand inclusion easily produced in traditional casting can be avoided; Good product quality, high process yield and high production efficiency. At the same time, as a new material forming process, squeeze casting also has the advantages of simple process, high material utilization, small machining allowance, energy saving and no waste discharge.

At present, the production of bucket teeth is mainly sand casting and investment casting. Because the molding materials used in sand casting are cheap and easy to obtain, the mold manufacturing is simple; However, there are often defects such as surface sand sticking, sand inclusion, inclusion, shrinkage cavity, shrinkage porosity and so on. Investment castings have high dimensional accuracy, low surface roughness and small machining allowance; However, a large riser needs to be set for feeding, which reduces the process yield. Xing Shuming and others invented the patent of using squeeze casting method to produce bucket teeth. During its test, there were defects such as incomplete forming, cracks, shrinkage cavities, porosity, pores, flow marks and so on. This paper analyzes the causes and prevention measures of these defects.

Through the analysis of the causes of bucket teeth defects, the adjustment of squeeze casting process parameters and the modification of relevant parts of the die were carried out, and the test was carried out again. The corresponding process parameters: when the preheating temperature of the die is (250 ± 10) ℃, the pouring temperature is 1620 ℃, the specific pressure of squeeze casting is 100MPa and the pressure holding time is 17s. The qualified bucket teeth are successfully trial produced. The effect is shown in Figure 1 and Figure 2.

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