Time-of-flight diffraction ultrasonics

About: Time-of-flight diffraction ultrasonics is a research topic. Over the lifetime, 544 publications have been published within this topic receiving 3189 citations.

TOFD detection verification method of large-scale spiral case welding seam

Abstract: The invention relates to a detection method of a spiral case welding seam. The TOFD detection verification method of a large-scale spiral case welding seam comprises the following steps: step one, preparing a sample, determining spiral case defect acceptance standards and TOFD detection technological parameters; step two, performing a spiral case welding seam contrast test in which TOFD, UT and RT are performed respectively, that is, firstly performing TOFD, then performing UT and RT respectively after detection, and finally dissecting unqualified defects determined respectively so as to verify respective detection accuracy; step three, performing a welding test plate contrast test, that is, preparing welding defects of cracks, incomplete fusion, lack of penetration, dense pores, slag inclusion, and the like on a test plate, and performing a contrast test with reference to step two; step four, performing contrast test analysis, and verifying TOFD reliability according to the defect detection rates of the three methods. The invention forms a TOFD, RT, and UT contrast test method of large-scale spiral case welding seams, and can be successfully applied to the detection of power station unit spiral case on-site installation welding seams.

Multi ultrasonic probe for scanning welded zone of tube

Abstract: Provided is to ultrasonic probe used in scanning defect of welded zone of tube, the ultrasonic probe includes a probe body having a predetermined length, a connection bar connected to one end of the probe body, a phased array ultrasonic sensor installed on one side surface of the probe body to scan positions and shapes of the defects, and a pair of time of flight diffraction (TOFD) sensors respectively installed in the same line with the phased array ultrasonic sensor therebetween to scan depths of the defects The present invention having the above-described configurations may significantly reduce a time taken to scan and accurately scan the positions, the shapes, and the depths of the defects

Pressure container weld transverse cracking TOFD (time of flight diffraction) detection scanner

Abstract: The utility model relates to a pressure container weld transverse cracking TOFD (time of flight diffraction) detection scanner. The scanner comprises a main frame, wherein magnetic wheel mechanisms are respectively arranged on four corners of the main frame, and each magnetic wheel mechanism comprises a magnetic wheel and a magnetic wheel bracket which is used for arranging the magnetic wheel on a corresponding position of the main frame; the main frame is provided with one or more probe loading arms, and part or all of the probe loading arms is provided with a probe; and the beam transmission direction of the probe and the horizontal direction form an included angle of between 30 and 60 degrees, and the probe comprises a TOFD probe. When the pressure container weld transverse cracking TOFD detection scanner is used for detecting a workpiece to be detected, the beam transmitted by the probe forms a certain included angle with the transverse cracking inside the workpiece to be detected; and after the beam transmitted by the probe is beat to the transverse cracking, the probe can receive more beam energy, and the transverse cracking inside the workpiece to be detected can be detected effectively.

Qualification of a combined ultrasonic inspection tool for detection and sizing of circumferential weld cracks in offshore pipelines

Abstract: The target of inline crack inspection is normally related to the detection of axial cracks (weld cracks, SCC etc.) as axial cracks are usually expected under typical loading conditions in pressurized pipe. Ultrasonic crack inspection tools for this type of cracks have been available for over 20 years and have become a standard application in the ILI business. However, under certain conditions circumferential cracking may occur and the inspection technique needs to be modified accordingly. Especially under offshore conditions with limited pipeline accessibility not only the early detection of crack-like defects is required but also a precise depth sizing is important in order to minimize the risk of crack-related pipeline failure. In order to ensure a high probability of detection together with state-of-the-art depth sizing, a 10″ inline inspection tool was developed for the detection of circumferentially orientated weld cracks. The tool combines the advantages of the pulse-echo technique on the detection side with the excellent capabilities of the TOFD (time-of-flight-diffraction) technique for accurate sizing. Both techniques are implemented into a tethered tool where the pulse-echo unit serves for fast screening while the relatively slow TOFD-unit is used for sizing of any detected crack-like features.In order to qualify the new tool for a special offshore application (inspection of circumferential cracking at welded anode pads) extensive testing was performed using a 10″ test pipeline prepared by Statoil. The test line contained 64 artificial weld defects for reference purposes as well as an unknown number of fatigue cracks in the weld area which were generated by fatigue testing of the corresponding pipes. The tests were full blind tests with no advance knowledge on locations and sizes of the cracks. The sizes of the fatigue cracks (length, depth) were determined by destructive examinations carried out after inline testing. The subsequent comparison of the destructive results with the non-destructive results showed that the specification of the tool with regard to detection and sizing was fully met. In the paper, the inspection concept and the setup of the new tool are described, and the results of the qualification tests are presented.Copyright © 2014 by ASME