集束超音波を用いたクラッド鋼の探傷試験

概要

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In order to detect precisely internal flaws at boundary surface of clad plates, ultrasonic testing with scanning device and focusing type probe are carried out on two subjects. First, the tests are made for various forms and dimensions of hole defects artifically drilled within test pieces, and accuracy and sensitivity of measurement and effects of flaw size and position on the echo pattern are evaluated. Secondary, the scanning tests are applied for explosively welded Al alloy- or mild steel-clad steel plates, and the areas of interfaces are finely inspected, the results of which are confirmed by microscopic examination on the sections of the plates. A summary of the results is shown below. When the focus of ultrasonic beam probe coincides with flaw position, it is possible to detect seperately two adjacent flaw 1mm away, and the sensitivity depends upon the focal diameter. Delayed echo, however, occurs when two flaws are too close together or the focus shifts from flaw position. The detectable depth of internal flaws depends upon the diameter and focal length of probe, and becomes deeper with increasing focal length and diameter. There are three types of flaw echo for boundary surface of clad plate, that is, lower wave-shaped, higher wave-shaped, and flat-shaped patterns reflected at interspersed flaws, large defect with interspersed flaws, and unwelded interface respectively.
社団法人溶接学会の論文
1983-03-05