Magnetic Bias – Eddy Current with superimposed DC field magnetization. Magnetic Bias is an electromagnetic form of inspection based on the Eddy Current principal with superimposed DC field magnetization to alter the permeability of the tube wall. It is a highly efficient and effective screening tool to sample large quantities of tubes rapidly and prioritize

Unlike all the tube inspection techniques which operate on magnetic or electromagnetic principles the IRIS, technique is based on ultrasonics. As shown in the attached illustration a beam from an ultrasonic transducer is reflected from a mirror set at 45 degrees so that the reflected ultrasonic beam impinges on the tube I.D. at right angles.

MFL is capable of detecting the presence and location of significant longitudinally or transversely orientated defects such as pits, scabs, slivers, gouges, roll-ins, laps, seams, cracks, holes and improper welds in ferromagnetic tubes under inspection. In addition, the severity of electromagnetic indication produced by the discontinuity may be estimated and a rejection level set with

Remote field testing (RFT) is applied in the testing of ferromagnetic heat exchanger tubes such as those made of carbon steel. The test is performed with a bobbin coil that transmits an electromagnetic field in the tube. These coils look similar to those for saturation only the housing is longer and there are two connections