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  • PCN Time of Flight Diffraction (TOFD)

    Time of flight diffraction (TOFD) method of ultrasonic testing is a sensitive and accurate method for the nondestructive testing of welds for defects. Measuring the amplitude of reflected signal is a relatively unreliable method of sizing defects because the amplitude strongly depends on the orientation of the crack. Instead of amplitude, TOFD uses the time of flight of an ultrasonic pulse to determine the position and size of a reflector.

    In a Time of Flight Diffraction (TOFD) system, a pair of ultrasonic probes sits on opposite sides of a weld. One of the probes, the transmitter, emits an ultrasonic pulse that is picked up by the probe on the other side, the receiver. In undamaged pipes, the signals picked up by the receiver probe are from two waves: one that travels along the surface and one that reflects off the far wall. When a crack is present, there is a diffraction of the ultrasonic wave from the tip(s) of the crack. Using the measured time of flight of the pulse, the depth of a crack tips can be calculated automatically by simple trigonometry

    NDTS India (P) Ltd is your one stop shop for PCN Time of Flight Diffraction (TOFD) level II in Mumbai.

    Advantages of Time of Flight Diffraction technique

    • Very High probability of detection and relatively low false call rate
    • Ability to detect discontinuities of any orientation
    • Ability to identify surface breaking discontinuity
    • Accuracy and reproducibility of measurement
    • High Speed Linear scanning

    Limitations of Time of Flight Diffraction Technique

    • Difficulties in detecting & discriminating discontinuities in sub surface zone (dead zone)
    • Dead zone near back wall
    • An inability to determine the lateral position of the indication in single scan.

    It is evident from the observations above that Time of Flight Diffraction (TOFD) training is a great idea. NDTS facilitates an in depth PCN Time of Flight Diffraction training course. We conduct Time of Flight diffraction testing course and our sole aim is that the trainee should receive QUALITY Time of Flight Diffraction training.

    A PCN TOFD Level II Training at NDTS Mumbai is an excellent first step to mastery in Time of Flight Diffraction testing techniques and a trainee would be able to immediately see the benefits in Time of Flight Diffraction testing. Some of the other courses offered are PCN PAUT Level II, PCN UT Level II.

    Responsibilities of Certified TOFD Level II

    An individual certified to Time of Flight Diffraction Level 2 has demonstrated competence to perform NDT according to Time of Flight Diffraction procedures. Within the scope of the competence defined on the certificate, Level 2 personnel may be authorized by the employer to

    • Select the Time of flight diffraction Testing technique for the test method to be used;
    • Define the limitations of application of the testing method;
    • Translate NDT codes, standards, specifications and procedures into NDT instructions adapted to the actual working conditions;
    • Set up and verify equipment settings;
    • Perform and supervise tests;
    • Interpret and evaluate results according to applicable standards, codes, specifications or procedures;
    • Carry out and supervise all tasks at or below level 2;
    • Provide guidance for personnel at or below level 2;
    • Report the results of Time of Flight Diffraction test.

    Days & Duration of UT Courses

    8 days training and 2 day exam (80Hrs)

    TOFD Level 2 training covers the following:

    Syllabus specific to Ultrasonic Testing of Welds using Time of Flight Diffraction 

    The PCN requirements of Training Hours & Work Experience for Level 2 TOFD are

    80 hours direct to Level 2, previous to the exam, and 12 months supervised work experience (Level 2 direct), to be obtained either before the examination, or within 24 months after passing the exam.

    Once the 40 additional hours training have been obtained, the examination passed, and 9 additional months supervised work experience obtained within 24 months of passing the exam, PCN will issue certification.

    Note: 12 months supervised work experience direct to Level 2, to be obtained either before the examination, or within 24 months after passing the exam.

    Following documents are required for PCN Examination

    TOFD Course – Enquiry

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