Indications of TOFD on HDPE – Termofusion or Material?

  • Indications of TOFD on HDPE – Termofusion or Material?

    Posted by william on 27/11/2021 at 4:13 pm

    Dear experts

    Im using ASTM-3044 for inspect HDPE and ASME B31.3 Table A341.3.2 as quality requirement. We are having indications on the record of TOFD, as an evidence of discontinuity.

    When they repaired, the indications persisted. And we could see pores on the bead and a pore on the chip when they prepare the surfaces of the Pipe.

    So my question is: the termofusion is making this or are inherent to the material?

    ASTM 3044 doesnt ask you for a mode conversion screen, so we are working only with the Compression mode

    jaden replied 7 months, 1 week ago 2 Members · 1 Reply
  • 1 Reply
  • Time of Flight Diffraction (ToFD)


    28/11/2021 at 1:28 pm
    1 Point

    firstly, the reason that ASTM EE3044 does not require the mode-converted time interval is because the shear mode is about 35dB lower than the P-mode so its amplitude will be insignificant.
    Both the preparation of the fusion surface and the material content could be sources of the indications. The contact surfaces of the pipe should be clean and dry. But it is also possible that there are inclusions in the HDPE pipe. A common source is unmixed carbon-black. Perhaps you could examine the chip under a microscope to see if you ca identify any impurities in the void.

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