Abstract: This study investigates the outer circular defects in centrifugally cast high-manganese aluminum bronze rings through anatomical analysis of the defects, as well as microscopic analysis methods such as metallography and energy spectroscopy to determine the types and causes of the defects. The results indicate that the defects are primarily point-shaped and linear slag inclusions, mainly composed of oxides such as Al₂O₃ and Si₂O₃. The formation of these defects is attributed to several factors: inadequate slag removal before centrifugal pouring, turbulence or splashing of the copper alloy liquid caused by deformation of the pouring nozzle tip leading to secondary oxidized slag entering the mold, and insufficient cleaning of residual coatings, oxides, and other impurities adhered to the plug-type pouring cup, plug, and taper sleeve. This research not only contributes to improving the qualification rate of high-manganese aluminum bronze rings but also provides valuable guidance for the centrifugal casting process of such components.