1.1 这种做法 2. 涵盖了应用涡流法检测铁磁管道中不连续性的程序( 附注1 ). 通过在检查线圈附近的区域施加集中的强磁场，可以使被检查的物品基本上无磁性，以提高对感兴趣缺陷条件的敏感性。 注1: 为方便起见，以下将使用术语管或管状产品来指代管道和管材。 1.2 该程序特别适用于使用环绕线圈组件的涡流检测方法。然而，采用固定或旋转探头的涡流技术- 线圈组件可用于增强大直径管状产品的不连续性灵敏度，或最大限度地提高从特定类型不连续性接收到的响应。 1.3 本规程适用于外径约为 1. / 4. 10英寸（6.35毫米至254.0毫米）。然而，这些技术已用于更小和更大的尺寸，并可能在买方和供应商之间的合同协议中指定。 1.4 这种做法没有建立验收标准；必须由使用方指定。 1.5 以英寸-磅单位表示的值应被视为标准值。 括号中给出的值是对国际单位制的数学转换，仅供参考，不被视为标准值。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如果有的话）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 =====意义和用途====== 5.1 本规程的目的是概述使用电磁（涡流）方法检测和定位铁磁管中凹坑、空隙、夹杂物、裂纹或突然尺寸变化等不连续性的程序。此外，可以指示不连续性的相对严重程度，并且可以根据指示的幅度设置拒绝级别。 5.2 自然不连续性的响应可能与钻孔或凹口等人工不连续性显著不同。因此，应做足够的工作来建立灵敏度水平和设置- 检测产品最终用途的自然不连续性。 5.3 涡流检测系统通常对管端附近的不连续性不敏感。末端效应区域的范围可以根据以下公式确定 8.6 . 5.4 由于涡流密度随着与外表面距离的增加而几乎呈指数级下降，因此对深部不连续性的响应降低，一些深部不间断性可能无法检测到。 5.5 不连续性方向也会影响系统响应，在确定检查灵敏度时应予以考虑。 5.6 在准备焊接管的参考标准时，如果预期响应不同，并且要检查两者，则应在焊接金属和母材中放置人工不连续性。然后调整该装置以获得最佳信噪比。 5.6.1 当仅检查焊接区域时，不连续性应仅放置在焊接区域。 5.7 在选择检查速度时，应考虑检查频率和使用的设备类型。某些类型的设备仅在给定的速度范围内有效；因此，检查速度应该落在这个范围内。 5.8 沿管子长度扫描的差动环绕线圈或探头可能并不总是能检测到在管子全长上连续均匀的不连续性，如划痕或接缝。

1.1 This practice 2 covers a procedure for applying the eddy current method to detect discontinuities in ferromagnetic pipe and tubing ( Note 1 ). The article being examined may be rendered substantially non-magnetic by the application of a concentrated, strong magnetic field in the region adjacent to the examining coil to enhance sensitivity to defect conditions of interest. Note 1: 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 testing 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 in. to 10 in. (6.35 mm 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. 1.4 This practice does not establish acceptance criteria; they must be specified by the using party or parties. 1.5 The values stated in inch-pound units are to be regarded as 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 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 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. 5.2 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. 5.3 Eddy current testing 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 . 5.4 Since the density of eddy currents decreases nearly exponentially as the distance from the external surface increases, the response to deep-seated discontinuities decreases and some deep-seated discontinuities may give no detectable repsonse. 5.5 Discontinuity orientation also affects the system response and should be taken into consideration when establishing the examination sensitivity. 5.6 In preparing a reference standard for welded tubing, artificial discontinuities should be placed in both the weld metal and the parent metal when the responses are expected to be different and if both are to be examined. The apparatus is then adjusted to obtain an optimum signal-to-noise ratio. 5.6.1 When examining only the weld area, the discontinuities shall be placed only in the weld area. 5.7 The examination frequency and the type of apparatus being used should be considered when choosing the examining speed. Certain types of equipment are effective only over a given speed range; therefore, the examining speed should fall within this range. 5.8 Discontinuities such as scratches or seams that are continuous and uniform over the full length of the tube may not always be detected with differential encircling coils or probes scanned along the tube length.