2015. Vol.18. No. 4, pp. 34-37
Procedure of NDT Instruments Qualification Tests. Classification of Ultrasonic Testing Devices
Method. Previous experience has shown that it is impossible to obtain defects with given parameters only by changing welding conditions. Defects were made mechanically or with electroerosive method. Size measurements were fulfilled with X-Ray tomograph; its measurement accuracy was confirmed by the results of metallographic study.
Results. 18 types of UT instruments have been tested on 5 types of weld bevels. Tests were fulfilled in accordance with DNV-OS-F-101 and DNV-RP-F118 standards. Welds’ unfoldings with indications of detected defects have been presented as well as average values and dispersion of absolute errors of defect parameters measuring. Classifications of UT instruments have been proposed – according to testing hardware implementation and to the methodology of ultrasound application. The results of NDT instruments qualification tests fulfilled in 2014 were used as the basis.
Conclusions. The fulfilled tests have made it possible to determine acceptability of each instrument for pipelines construction and repair.
Keywords: ultrasonic testing, pipes, welds, model of a defect, X-Ray tomography
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