Abstract：In order to obtain the installation posture of flange end faces in multi-branch welded pipelines quickly and accurately, a flexible measurement tool, together with a calibration procedure, is proposed for visual inspection. Each flange end face is fxed by the measurement tool’s claw, whose scalability could adjust to various types of pipelines with different diameters. In addition, the measurement tool possesses a good self-centering capability. A number of visual target points are laid on the bottom of the measurement tool. By visually measuring the target points on the calibrated measurement tool, a measurement coordinate system can be built up, which could represent the normal vector, the location of center point and circumferential position of the flanges. The experiments show that the absolute location accuracy of the flanges end faces is 0.070mm, and the double standard deviation of repeated positioning is 0.044mm.
2022, 
