Significance and Use
5.1 The purpose of this practice is to outline a procedure for the in-line eddy current examination of hot CW pipe for the detection of major imperfections and repetitive discontinuities.
5.2 A major advantage of in-line eddy current examination of ferromagnetic CW pipe above the Curie temperature lies in the enhanced signal-to-noise ratio and depth of penetration obtained without the use of magnetic saturation.
5.3 The eddy current method is capable of detecting and locating weld imperfections commonly referred to as open welds, cave welds, black spots (weld inclusions), and partial welds (incomplete penetration). In addition, it will detect pipe-wall imperfections such as slivers, laps, and ring welds (end welds).
5.4 The relative severity of the imperfections may be indicated by eddy current signal amplitude or phase, or both. An alarm level may be selected that utilizes signal amplitude or phase, or both, for automatic recording or marking, or both.
5.5 Because the responses from natural discontinuities may vary significantly from those from artificial discontinuities, care must be exercised in establishing test sensitivity and acceptance criteria.
1.1 This practice covers a procedure for in-line, eddy current examination of continuously welded (CW) ferromagnetic pipe and tubing at temperatures above the Curie temperature (approximately 1400°F (760°C), where the pipe is substantially nonmagnetic or austenitic.
1.2 This practice is intended for use on tubular products having nominal diameters of 1/2 in. (12.7 mm) to 4 in. (101.6 mm). These techniques may be used for larger- or smaller-diameter pipe and tubing as specified by the using parties.
1.3 This practice is specifically applicable to eddy current testing using encircling coils, or probe coils.
1.4 This practice does not establish acceptance criteria. They must be established by the using parties.
1.5 Units—The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.6 This standard does not purport to address the safety problems 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.