MPI for inspecting the inside diameter of tubes for transverse oriented defects

  • MPI for inspecting the inside diameter of tubes for transverse oriented defects

    Posted by chris on 21/05/2021 at 6:45 am

    Dear Experts,
    How to inspect the inside diameter of ferromagnetic heavy wall pipes or API Casing hanger tubes by Magnetic particle testing for defects oriented in transverse direction.

    Transverse defects at OD can be covered by coil shot/flexible cable wrap units by employing longitudinal magnetization technique.

    Longitudinal defects at ID can be detected by central conductor technique by circular magnetization and some extent at OD by using high current.

    Is there any effective way to detect transverse defects at ID of pipe?

    Thanks

    nde replied 3 years, 6 months ago 2 Members · 1 Reply
  • 1 Reply
  • Magnetic Particle Inspection (MPI) (MT)

    nde

    Member
    21/05/2021 at 6:46 am

    A head shot would be current flow and the alternative current flow through a central conductor wouldn’t detect transverse defects.
    You need induced magnetism/magnetic flow with current flowing in a circular direction to induce longitudinal magnetism.
    You need to do the calculations but I suspect the current required for a coil or encircling cables would be impractical.
    A small yoke on a a rod or buggy could apply local magnetisation but you also need to apply fluorescent particles and have a camera. These aren’t technically difficult but not a simple task either and probably fairly slow.

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