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Thin welds
Update (1.07.2010)

Ultrasonic testing of welds with a thickness of 2 to 8mm

The need for non-destructive testing of welds of small thickness, unfortunately, has been confirmed in many accidents, sometimes especially in Power Engineering, whitch were disasters. The requirements of the supervisory bodies, investors, and economy create a need for such studies, often with a range of many thousands of pieces (pipe) or meters (structures). However, in this respect the existing state of standardization in the two basic methods ie UT and RT is not perfect. UT research standards do not provide welds testing in less than 8 mm, while standard on the RT provide for such testings but their credibility is particularly low. This low reliability, due to geometric mismatch of the incident beam to glues in the weld defects that are particularly dangerous in this range of thickness.
In the test tube weld, it is difficult to detect glue on the end or the initiation of the peripheral joints of the pipe. It is a defect with a small size that occurs in these joints the most, and also (because of its rapid development) the most dangerous because it causes frequent breakdowns. Such UT detection method is difficult, because it is a "small defect" is located radially next "big" peripheral face of inequality and the ridge. Such tests are necessary, however, and it allows the specific selection of parameters of probes the construction and calibration of tests IBUS-TD method. Using methods that are insufficiently provide this type of detection of defects is a serious technical error. In particular, radiographic tests should not be used, because the probability of detecting most dangerous defect is negligible. However, in ultrasonic testing when using special probes and conditions Instructions IBUS-TD better than satisfactory results have been achieved. This is confirmed in the qualification of the method carried out by the Office of Technical Inspection and recognition methods for testing equipment under supervision of OTI.

Certificates awarded by the Office of Technical Inspection (in polish)

Examination of thin welds according to IBUS-TD method. To order it in foreign language click here
Reliability of thin welds [pdf](download, 709 kB)

The film presents the study of thin welds IBUS-TD method