1.1 这种做法 2. 介绍了镍和镍合金管的涡流检测程序。这些程序适用于外径不超过2英寸（50.8 mm）、壁厚为0.035英寸至0.120英寸（0.889 mm至3.04 mm）的管道，包括本标准适用于将传感器放置在管道外表面的程序。根据买方和生产商之间的合同协议，这些程序可用于超出建议尺寸范围的管道。 1.2 本实践中描述的程序使用固定的环绕测试线圈或探针系统。 1.3 单位-- 以英寸表示的值- 磅单位应视为标准单位。括号中给出的值是国际单位制的数学转换，仅供参考，不被视为标准。 注1: 为方便起见，以下将使用术语“管材”或“管材产品”来指代管材和卡套管。 1.4 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 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 涡流检测是一种无损检测金属材料不连续性的方法。信号可以由源自管的外表面或内表面的不连续性产生，也可以由完全包含在壁内的不连续产生。由于涡电流的密度随着离线圈最近的表面距离的增加而几乎呈指数级下降，因此对深层缺陷的响应相应地降低。相位变化也与深度变化相关，从而允许使用相位分析技术。 5.2 自然不连续性的响应可能与人工不连续性（如钻孔或缺口）的响应明显不同。 出于这个原因，应该做足够的工作来确定灵敏度水平和所需的设置，以检测对产品最终用途有影响的自然不连续性。 5.3 通过这种方法获得的一些指示可能与产品质量无关；例如，不相关的指示可能是由微小的凹痕或工具震颤痕迹引起的，这些凹痕或痕迹对产品的最终用途没有损害。不相关的显示可能掩盖不可接受的不连续性。相关指示是由不连续性引起的指示。任何超过拒收水平的指示应被视为相关指示，直到可以证明其无关。 5.4 通常，涡流检测系统对管道端部附近的不连续性不敏感（端部效应）。 5.5 在管道全长上连续且均匀的不连续性（如划痕或接缝）可能并不总是通过沿管道长度扫描的差分环绕线圈或探针来检测。 5.6 对于有磁性的材料，应在检查线圈的区域内放置强磁场。磁场也可用于提高表现出轻微残余磁性的管道中的信噪比。

1.1 This practice 2 covers the procedures for eddy-current examination of nickel and nickel alloy tubes. These procedures are applicable for tubes with outside diameters up to 2 in. (50.8 mm), incl, and wall thicknesses from 0.035 in. to 0.120 in. (0.889 mm to 3.04 mm), incl. This standard applies to procedures where the sensor is placed on the outside surface of the tube. These procedures may be used for tubes beyond the size range recommended, by contractual agreement between the purchaser and the producer. 1.2 The procedures described in this practice make use of fixed encircling test coils or probe systems. 1.3 Units— 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. Note 1: For convenience, the term “tube” or “tubular product” will hereinafter be used to refer to both pipe and tubing. 1.4 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. 1.5 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 Eddy-current testing is a nondestructive method of locating discontinuities in metallic materials. Signals can be produced by discontinuities originating on either the external or internal surfaces of the tube or by discontinuities totally contained within the wall. Since the density of eddy currents decreases nearly exponentially with increasing distance from the surface nearest the coil, the response to deep-seated defects decreases correspondingly. Phase changes are also associated with changes in depth, allowing the use of phase analysis techniques. 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 setup required to detect natural discontinuities of consequence to the end use of the product. 5.3 Some indications obtained by this method may not be relevant to product quality; for example, an irrelevant indication may be caused by minute dents or tool chatter marks, which are not detrimental to the end use of the product. Irrelevant indications can mask unacceptable discontinuities. Relevant indications are those which result from discontinuities. Any indication that exceeds the rejection level shall be treated as a relevant indication until it can be demonstrated that it is irrelevant. 5.4 Generally, eddy-current examination systems are not sensitive to discontinuities adjacent to the ends of the tube (end effect). 5.5 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. 5.6 For material that is magnetic, a strong magnetic field shall be placed in the region of the examining coil. A magnetic field may also be used to improve the signal-to-noise ratio in tubing that exhibits slight residual magnetism.