铸造闭式叶轮内型面荧光渗透检测

Detection for Inner Surface Defect of Casting Enclosed Impeller by Fluorescent Penetrant Inspection

铸造闭式叶轮零件的内型面液浸法荧光渗透检测中存在内型面清洗困难、内型面荧光显示区域观察及尺寸测量困难等问题,利用自制的补充清洗工具,采用带UV光源的柔性紫外线视频内窥镜观察荧光显示及双目显示尺寸测量,研究结果表明:采用补充清洗工具清洗后,大大减少了内型面检测中的背景干扰显示,双目测量中必须控制轴线内窥镜与缺陷平面法线夹角在20°以内才能保证荧光显示尺寸测量精度±0.2 mm要求。经过实际零件检测和金相解剖分析,零件的内型面荧光显示主要集中在流道面的转接R处,其主要呈现片状分布,少数有线状显示,荧光显示来源于铸造疏松,荧光渗透检测有效显示尺寸采用双目测量的结果与解剖后直接测量结果的误差在±0.2 mm内。

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.