The purpose of this practice is to outline a procedure for the detection and location of discontinuities such as pits, voids, inclusions, cracks, or abrupt dimensional variations in ferromagnetic tubing using the electromagnetic (eddy-current) method. Furthermore, the relative severity of a discontinuity may be indicated, and a rejection level may be set with respect to the magnitude of the indication.

The response from natural discontinuities can be significantly different than that from artificial discontinuities such as drilled holes or notches. For this reason, sufficient work should be done to establish the sensitivity level and set-up required to detect natural discontinuities of consequence to the end use of the product.

Eddy-current examination systems are generally not sensitive to discontinuities adjacent to the ends of the tube. The extent of the end effect region can be determined in accordance with 8.6.

1.1 This practice covers a procedure for applying the eddy-current method to detect discontinuities in ferromagnetic pipe and tubing (Note 0) where the article being examined is rendered substantially non-magnetic by the application of a concentrated, strong magnetic field in the region adjacent to the examining coil. For convenience, the term tube or tubular product will hereafter be used to refer to both pipe and tubing.

1.2 The procedure is specifically applicable to eddy-current examination methods using an encircling-coil assembly. However, eddy-current techniques that employ either fixed or rotating probe-coil assemblies may be used to either enhance discontinuity sensitivity on the large diameter tubular products or to maximize the response received from a particular type of discontinuity.

1.3 This practice is intended for use on tubular products having outside diameters from approximately 1/4 to 10 in. (6.35 to 254.0 mm). These techniques have been used for smaller and larger sizes however, and may be specified upon contractual agreement between the purchaser and the supplier.