Ultrasonic Surface Examinations Using Electromagnetic Acoustic Transducer (EMAT) Techniques

1.1 This test method covers guidelines for utilizing EMAT techniques for detecting material discontinuities that are primarily open to the surface (for example, cracks, seams, laps, cold shuts, laminations, through leaks, lack of fusion). This technique can also be sensitive to flaws and discontinuities that are not surface-breaking, provided their proximity to the surface is less than or equal to the Rayleigh wave length. 1.2 This test method covers procedures for the non-contact coupling of surface waves into a material via electromagnetic fields. 1.3 The procedures of this test method are applicable to any material in which acoustic waves can be introduced electromagnetically. This includes any material that is either electrically conductive or ferromagnetic, or both. 1.4 This test method is intended to provide examination capabilities for in-process, final, and maintenance applications. 1.5 This test method does not provide standards for the evaluation of derived indications. Interpretation, classification, and ultimate evaluation of indications, albeit necessary, are beyond the scope of this document. Separate specifications or agreement will be necessary to define the type, size, location, and direction of indications considered acceptable or nonacceptable. 1.6 The values stated in inch-pound units are to be regarded as the standards. The SI units given in parentheses are for information only. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.