Excavators are widely used in highway, bridge, construction, breeding pond, underground engineering, emergency excavation and other engineering construction fields. It is characterized by large power and high efficiency. The hydraulic multi-channel valve control system is one of the heart components of excavator, and the multi-channel valve body is its key part. At present, this multi-channel valve is mainly imported from abroad. There are few units in China that can stably produce in mass and meet the casting requirements.
The casting brand of multi-way valve developed by ZHY casting test is QT500-7, with a mass of 89 kg and an overall dimension of 360 mm × 265mm × 65 mm。
The production test is carried out again for the process improvement and adjustment. The inspection results of the casting show that the broken core defect has disappeared, the deformation tendency has been effectively controlled, the maximum deformation is 0.6 mm, and the defects on the upper surface of the casting have been greatly improved, but not completely eliminated.
Several production tests have been carried out by using the above process, and a total of more than 30 castings have been produced. The quality of the castings is stable and consistent. Through the machining and installation test conducted by the customer, the size, mechanical properties and compactness of the castings fully meet the requirements. The test results show that the process design scheme of this type of multi-channel valve body is feasible under the existing production conditions, and can carry out small batch trial production. However, the surface pitting defect needs further measures to be completely solved.