Discussion on Non-Destructive Testing Method for Transverse Crack of Butt Weld of Spherical Tank
The butt welds of three LPG spherical tanks in a petrochemical plant were tested by 100％TOFD detection and 100％ultrasonic detection on the outer surface.Lateral buried defects were found during the inspection.Ultrasonic testing and y-ray testing were used to retest the transverse defects.The characteristics of transverse cracks in the TOFD map were analyzed and verified by on-site anatomical penetration testing.The characteristics of the transverse crack map are that the two ends of the arc parabola are longer,the top of the parabola is sharp and the black and white gray scale is not obvious.When the transverse crack feature map appears,supplementary testing is required to screen and confirm the transverse crack.At the same time,the ultrasonic detection K1 probe is used to perform parallel scanning on the suspected parts to determine whether it is a transverse crack or a point defect.The combination of TOFD detection and ultrasonic detection improves the accuracy of TOFD non-parallel scanning detection results of weld transverse cracks,and reduces the probability of missed detection of transverse cracks by TOFD non-parallel scanning detection.
transverse crack of weldTOFD non-parallel detectionthe anatomy of the validation
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