1.1 这种做法 2. 用于标准化用于检查无缝铝合金管的涡流设备。采用由平底孔或通孔或两者组成的人工不连续性作为标准化涡流系统的手段。包括涡流检测程序的一般要求。 1.2 参考标准的制造程序见 X1.1 和 X2.1 . 1.3 本规程旨在检验公称直径不超过4英寸的管状产品。（101.6 mm）和壁厚，达到被检查的特定合金（电导率）的涡流标准穿透深度（SDP）和使用的检查频率。 注1: 只要获得足够的分辨率并符合使用方的规定，这种做法也可用于直径较大或壁厚较重的涡流有效穿透深度（EDP）。 1.4 本惯例未建立验收标准。必须由使用方建立。 1.5 单位- 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户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。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 通过将管子纵向穿过或靠近用一个或多个频率的交流电通电的涡流传感器来进行检查。涡流传感器的电阻抗随管道的接近程度而变化。这种修改的程度取决于涡流传感器和管道之间的距离、管道的尺寸和电导率。管中存在冶金或机械不连续性将改变涡流传感器的视在阻抗。在管道通过期间，由管道局部差异引起的涡流传感器特性变化产生电信号，电信号被放大和修改，以驱动音频或视觉信号装置或机械标记，以指示管道长度中的不连续位置。 信号可以由位于管外表面或内表面的不连续性或完全包含在管壁内的不连续性产生。 4.2 涡流在管壁中的穿透深度受被检查材料的电导率（合金）和所用激励频率的影响。根据标准穿透深度方程的定义，涡流穿透深度与电导率和激励频率成反比( 注释2 ). 超过一个标准穿透深度（SDP），涡流检测不连续性的能力降低。当壁厚不超过SDP时，无缝铝合金管的电磁检测最为有效，或者当感兴趣的不连续性在一个SDP内时，在较重的管壁中，电磁检测最为有效。通过传统涡流传感器检测冶金或机械不连续性的极限通常被接受为约为SDP点的三倍，称为有效穿透深度（EDP）。 注2: 标准贯入深度由以下等式定义: 哪里: SDP公司 = 一个标准贯入深度，m， f = 频率，Hz（每秒周期数），和 σ = 电导率，西门子/米。 或: 哪里: SDP公司 = 一个标准贯入深度，in。， f = 频率（Hz）（每秒周期数），以及 σ = 电导率， % IACS。

1.1 This practice 2 is for standardizing eddy current equipment employed in the examination of seamless aluminum-alloy tube. Artificial discontinuities consisting of flat-bottomed or through holes, or both, are employed as the means of standardizing the eddy current system. General requirements for eddy current examination procedures are included. 1.2 Procedures for fabrication of reference standards are given in X1.1 and X2.1 . 1.3 This practice is intended for the examination of tubular products having nominal diameters up to 4 in. (101.6 mm) and wall thicknesses up to the standard depth of penetration (SDP) of eddy currents for the particular alloy (conductivity) being examined and the examination frequency being used. Note 1: This practice may also be used for larger diameters or heavier walls up to the effective depth of penetration (EDP) of eddy currents as long as adequate resolution is obtained and as specified by the using party or parties. 1.4 This practice does not establish acceptance criteria. They must be established by the using party or 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 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 ====== 4.1 The examination is performed by passing the tube lengthwise through or near an eddy current sensor energized with alternating current of one or more frequencies. The electrical impedance of the eddy current sensor is modified by the proximity of the tube. The extent of this modification is determined by the distance between the eddy current sensor and the tube, the dimensions, and electrical conductivity of the tube. The presence of metallurgical or mechanical discontinuities in the tube will alter the apparent impedance of the eddy current sensor. During passage of the tube, the changes in eddy current sensor characteristics caused by localized differences in the tube produce electrical signals which are amplified and modified to actuate either an audio or visual signaling device or a mechanical marker to indicate the position of discontinuities in the tube length. Signals can be produced by discontinuities located either on the external or internal surface of the tube or by discontinuities totally contained within the tube wall. 4.2 The depth of penetration of eddy currents in the tube wall is influenced by the conductivity (alloy) of the material being examined and the excitation frequency employed. As defined by the standard depth of penetration equation, the eddy current penetration depth is inversely related to conductivity and excitation frequency ( Note 2 ). Beyond one standard depth of penetration (SDP), the capacity to detect discontinuities by eddy currents is reduced. Electromagnetic examination of seamless aluminum alloy tube is most effective when the wall thickness does not exceed the SDP or in heavier tube walls when discontinuities of interest are within one SDP. The limit for detecting metallurgical or mechanical discontinuities by way of conventional eddy current sensors is generally accepted to be approximately three times the SDP point and is referred to as the effective depth of penetration (EDP). Note 2: The standard depth of penetration is defined by the following equations: where: SDP = one standard depth of penetration, m, f = frequency, Hz (cycles per second), and σ = conductivity, Siemens/metre. or: where: SDP = one standard depth of penetration, in., f = frequency in Hz (cycles per second), and σ = conductivity, % IACS.