Any conductive tubing material such as Brass, Stainless Steel, and Inconel tubes can be inspected. Special multi-frequency signal mixing is required to separate signals from ferromagnetic tube sheet and tube supports.
Electromagnetic Nondestructive Testing (NDT) referred to as Eddy Current Testing, (ET or ECT) is used for detection of service induced defects. The ET examination is an NDT method for the detection of surface and slightly subsurface defects such as cracks, pits, wall thinning, and wear located on I.D. and O.D. of thin tubing.
Multi-frequency ET systems consist of the following:
–Instrument – Single & Multi-frequency
–Probe – Special designs for each application
–Standard – Same conductivity as tested part with real or simulated defects
Analysis of ET data relies on phase and amplitude of ET signals on CRT scope or similar devices.