Fracture Analysis of an Aluminum Alloy Gear Pump Housing

Abstract:

The gear pump housing in bulldozer, which was made of cast Al-Si alloy, was found to break in two halves during running. In order to determine fracture reason of the gear pump housing failure analysis in detail were conducted by visual inspection, optical microscope and scanning electron microscope (SEM), chemical analysis, hardness inspection. Visual inspection showed that the crack source has a white semicircle on the interior side of the section and propagated toward the exterior surface of the housing with obvious radial state. Meanwhile, the inner wall has the wear trace in depth of 0.1 mm due to boring phenomenon. SEM observation indicated brittle cleavage fracture mechanism with many casting defects such as dendritic shrinkage and inclusion as well as initiated crack in gear pump housing. The casting defects probably promoted the initiation and propagation of the crack and decreased the loading capacity of the gear to impacting force from the inside shaft. The analysis results show that the failure of gear pump housing mainly resulted from serious boring phenomenon, dendritic shrinkage and the lower material performance.

• Periodical: Key Engineering Materials (Volume 723)
• Pages: 288-293
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.723.288
• Online since: December 2016
• Authors: Ping Li*, Yan Jie Zhao, Chun Qing Ma
• Keywords: Cast Aluminum Alloys, Crack, Failure Analysis, Fracture, Gear Pump Housing

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