Eddy Current Testing (ET)

ET is one of many electromagnetic testing methods used in nondestructive testing (NDT) making use of electromagnetic induction to detect and characterize surface and sub-surface flaws in conductive materials.

In its most basic form — the single-element ECT probe — a coil of conductive wire is excited with an alternating electrical current. This wire coil produces an alternating magnetic field around itself. The magnetic field oscillates at the same frequency as the current running through the coil. When the coil approaches a conductive material, currents opposite to the ones in the coil are induced in the material — eddy currents

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ET is utilized in many industries ranging from aerospace, boilers, piping inspection and even coating inspection. 

  • Can detect discontinuities, conductivity,

  • Can only be used on conductive materials.

  • Depth of penetration is roughly 0.230"

  • High Inspection speeds

  • Extensive Technician training required

  • Portable

  • Sensitive to small defects

  • Immediate results

What can ET measure?

  • Crack Detection

  • Material thickness measurements

  • Coating thickness measurements

  • Conductivity measurements for:

    • Material identification

    • Heat damage detection

    • Case depth determination

    • Heat treatment monitoring

What Material can ET Test?

  • Aircraft structures, units, and engines

  • Boilers, heat exchangers, cast iron pipes, and pipelines using remote field testing

  • Gears, blades, bolts, bolt holes, threading, shafts, flanges, nozzles

  • Manufacturing and transportation equipment

  • Automotive parts

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