1.1 本规程为使用磁致伸缩换能器产生的波进行导波测试（GWT）焊接管件提供了指南。磁致伸缩材料将时变磁场转换成机械能。当磁致伸缩材料被磁化时，它会变形。相反，如果外力在磁致伸缩材料中产生应变，材料的磁性状态将发生变化。磁致伸缩材料的磁性和机械状态之间的这种双向耦合提供了可用于致动和感测装置的转换能力。 1.2 GWT利用10至约250 kHz范围内的超声波引导波，沿管道轴向发送至非- 通过检测管道横截面或刚度的变化或两者，对管道进行破坏性测试，以确定不连续性或其他特征。 1.3 GWT是一种筛选工具。该方法不能直接测量壁厚或不连续性的准确尺寸。然而，可以获得不连续性严重程度的估计。 1.4 本规程适用于公称管道尺寸（NPS）为2至48，对应于60.3至1219.2 mm（2.375至48 英寸）外径和壁厚在3.81和25.4 mm之间（0.15和1 英寸）。 1.5 此实践仅适用于基本管道配置的GWT。这包括直管，采用单一管道尺寸和规格制造，在测试位置完全可接近，通过环焊缝连接，由简单接触支撑支撑，无内部或外部涂层，或两者兼而有之； 管道可以是绝缘的或涂漆的。 1.6 本规程提供了进行考试的一般规程。所获得的导波数据的解释是复杂的，需要进行训练才能正确地进行数据解释。 1.7 这一做法并未确立验收标准。认可工程师应在合同协议中规定具体验收标准。 1.8 单位- 以国际单位制表示的值应视为标准值。括号中给出的值是对SI单位的数学转换，仅供参考，不被视为标准值。 1.9 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。 1.10 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《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 5.1 本规程的目的是概述使用GWT定位金属管道中因腐蚀或侵蚀而发生壁损的区域的程序。 5.2 GWT不能直接测量壁厚，但对CSC（或反射）的组合很敏感 系数，系数 )以及任何金属损失的周向范围和轴向范围。根据这些信息，可以指定严重性的分类。 5.3 GWT方法提供了一种筛选工具，可以快速识别管道上的任何不连续性。如果发现可能的缺陷，通常需要使用超声波检测或其他无损检测方法对可疑区域进行后续检查，以获得详细的厚度信息、性质和损坏程度。 5.4 GWT还提供了一些关于不连续性轴向长度的信息，前提是轴向长度大约比波长的四分之一长。 5.5 任何可能缺陷的识别和严重性评估仅限于定性。区分相关和非相关信号的解释过程是必要的。 5.6 本规程仅涵盖范围中规定的应用。GWT方法具有一定的能力，可用于管道绝缘、埋地、道路交叉口以及通道受限的应用。 5.7 GWT应由合同或采购订单中规定的合格认证人员执行。资格认证应包括所用设备的使用、测试结果的解释和导波技术的培训。 5.8 供应商应保存一份文件化计划，包括GWT人员认证的培训、考试和经验。

1.1 This practice provides a guide for the use of waves generated using magnetostrictive transduction for guided wave testing (GWT) welded tubulars. Magnetostrictive materials transduce or convert time varying magnetic fields into mechanical energy. As a magnetostrictive material is magnetized, it strains. Conversely, if an external force produces a strain in a magnetostrictive material, the material’s magnetic state will change. This bi-directional coupling between the magnetic and mechanical states of a magnetostrictive material provides a transduction capability that can be used for both actuation and sensing devices. 1.2 GWT utilizes ultrasonic guided waves in the 10 to approximately 250 kHz range, sent in the axial direction of the pipe, to non-destructively test pipes for discontinuities or other features by detecting changes in the cross-section or stiffness of the pipe, or both. 1.3 GWT is a screening tool. The method does not provide a direct measurement of wall thickness or the exact dimensions of discontinuities. However, an estimate of the severity of the discontinuity can be obtained. 1.4 This practice is intended for use with tubular carbon steel products having nominal pipe size (NPS) 2 to 48 corresponding to 60.3 to 1219.2 mm (2.375 to 48 in.) outer diameter, and wall thickness between 3.81 and 25.4 mm (0.15 and 1 in.). 1.5 This practice only applies to GWT of basic pipe configuration. This includes pipes that are straight, constructed of a single pipe size and schedules, fully accessible at the test location, jointed by girth welds, supported by simple contact supports and free of internal, or external coatings, or both; the pipe may be insulated or painted. 1.6 This practice provides a general practice for performing the examination. The interpretation of the guided wave data obtained is complex and training is required to properly perform data interpretation. 1.7 This practice does not establish an acceptance criterion. Specific acceptance criteria shall be specified in the contractual agreement by the cognizant engineer. 1.8 Units— The values stated in SI 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. 1.9 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. 1.10 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 using GWT to locate areas in metal pipes in which wall loss has occurred due to corrosion or erosion. 5.2 GWT does not provide a direct measurement of wall thickness, but is sensitive to a combination of the CSC (or reflection coefficient ) and circumferential extent and axial extent of any metal loss. Based on this information, a classification of the severity can be assigned. 5.3 The GWT method provides a screening tool to quickly identify any discontinuity along the pipe. Where a possible defect is found, a follow-up inspection of suspected areas with ultrasonic testing or other NDT methods is normally required to obtain detailed thickness information, nature, and extent of damage. 5.4 GWT also provides some information on the axial length of a discontinuity, provided that the axial length is longer than roughly a quarter of the wavelength. 5.5 The identification and severity assessment of any possible defects is qualitative only. An interpretation process to differentiate between relevant and non-relevant signals is necessary. 5.6 This practice only covers the application specified in the scope. The GWT method has the capability and can be used for applications where the pipe is insulated, buried, in road crossings, and where access is limited. 5.7 GWT shall be performed by qualified and certified personnel, as specified in the contract or purchase order. Qualifications shall include training specific to the use of the equipment employed, interpretation of the test results, and guided wave technology. 5.8 A documented program which includes training, examination, and experience for the GWT personnel certification shall be maintained by the supplying party.