ZL101A铝合金轴承座断裂原因分析

Analysis of Fracture Causes of ZL101A Aluminum Alloy Bearing Housing

ZL101A铝合金轴承座在服役过程中发生严重的断裂失效问题,对其化学成分、硬度、金相组织及断口形貌等进行表征和分析,确定轴承座开裂性质和原因。结果表明:轴承座断裂模式为疲劳断裂,导致断裂的主要原因为轴承座材质存在严重的缩松缺陷,应力在缩松缺陷部位集中,逐渐萌生裂纹,导致断裂失效。缩松缺陷产生的原因为金属液补缩不充分或浇注过程中卷入大量气体。在设计浇注系统时,建议设置暗冒口可有效预防铸件产生该类型缩松缺陷,为铸造缺陷改善提供借鉴。

In order to analyze the fracture failure cause of ZL101A aluminum alloy bearing housing, its chemical composition, hardness, metallographic structure and fracture morphology were characterized and analyzed,and the properties and causes of bearing housing fracture were determined. The results showed that the fracture mode of the bearing housing was fatigue fracture, due to a serious shrinkage defects in the material of the bearing housing. The stress was concentrated at the shrinkage porosity defect, and cracks were gradually initiated, resulting in fracture failure. The main cause of shrinkage defects may be the insufficient feeding of the molten metal at the thin-wal ed structure or the involvement of a large amount of gas during the pouring process.By adding blind riser when designing the gating system, this type of shrinkage defects can be effectively prevented in castings, and provide a reference for the improvement of casting defects.