A Study of Inspection Systems for Welded Products. Part 7: A Tandem Probe Technique for Determination of the Height of Planar Defects

摘要

The tandem probe technique is able to determine the size of interior planar defects of the lack-of-penetration type and defects with a similar geometry. The size should be larger than the ultrasonic wavelength, smaller than the largest detectable defect size (P sub max). The method is reasonably accurate, with a standard deviation approximately 0.5 mm. Preparation of special reference test pieces is - at least until the theoretical background is clarified - a necessity for each range of material thickness. Careful calibration must be done prior to all determinations of defect size. (Copyright (c) The Danish Welding Institute 1978.)