Abstract:
There exist some difficulties in fluorescence penetration inspection of casting enclosed impeller parts, such as cleanout of inner surface, and observation and dimensional measurement of fluorescent display regions of inner surface. In this paper, a self-made supplementary cleaning tool and a flexible ultraviolet video endoscope with UV source were employed for observation of fluorescent display and binocular dimensional measurement. The results indicate that the background interference display on inner surface was decreased considerably with the supplementary cleaning tool. In addition, the angle between the axis of endoscope lens and the normal line of the defect plane must be controlled within 20 degrees to ensure the measurement accuracy of the fluorescent display size (±0.2 mm) in binocular measurement. By the actual part inspection and metallographic anatomy analysis, the fluorescent displays of the inner surface resulting from casting shrinkage mostly clustered in R corner of the flow passage surface, mainly appearing as sheet distribution combined with a few linear displays. The error between binocular and direct measurement result after dissection was within 2 mm.
