1.1 本指南提供了指导信息，并描述了测量表面开放的平面缺陷高度的原理和超声波检查技术。本标准指南中描述的实践和技术旨在作为选择特定超声波探伤技术以及建立仪器标准化方法时使用的参考。 2. 1.2 本标准指南不提供或建议所述技术的精度或公差。搜索单位、检查表面条件、材料成分等参数都会影响结果的准确性。建议用户评估适用于每个应用的精度和公差。 1.3 本指南无意提供测量缺陷长度的指导。 1.4 本标准指南未提供、建议或规定验收标准。 进行缺陷尺寸评估后，应将结果应用于规定验收标准的适当规范或标准。 1.5 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 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，并确定法规要求的适用性。 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《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 本文件中引用的实践适用于测量源于部件远表面或近表面的表面上的平面缺陷的高度。这些做法适用于机械或热疲劳缺陷、应力腐蚀缺陷或任何其他表面连接平面缺陷的穿墙尺寸。 5.2 概述的技术描述了使用折射纵波和横波技术对铁素体或奥氏体部件进行超声波探伤的实践及其相关限制。可使用本指南和适当的标准化参考块检查其他材料。所述实践适用于手动和自动检查。 5.3 本标准指南中推荐的技术使用飞行时间（TOF）或飞行时间增量（ΔTOF）方法来准确测量缺陷尺寸。本指南不包括使用信号振幅法确定缺陷尺寸。 5.4 通常，使用这些尺寸确定方法，将要确定尺寸的材料体积（或部件厚度）分为三分之一；内部 1. / 3. ，中间 1. / 3. 和附近 1. / 3. 使用远表面爬行波方法，用户可以定性地将缺陷分离为近似值 1. / 3. 区 5.5 尺寸调整方法用于 1. / 3. 定量确定裂纹尺寸的区域，即尖端衍射 1. / 3. ，中间采用双模态法 1. / 3. ，以及近期的聚焦纵波或聚焦横波方法 1. / 3. 这些 1. / 3. 区域通常适用于大多数尺寸调整应用，但是，各种尺寸调整方法也适用于这些应用之外的应用 1. / 3. 区域提供了适当的参考块和技术。

1.1 This guide provides tutorial information and a description of the principles and ultrasonic examination techniques for measuring the height of planar flaws which are open to the surface. The practices and technology described in this standard guide are intended as a reference to be used when selecting a specific ultrasonic flaw sizing technique as well as establishing a means for instrument standardization. 2 1.2 This standard guide does not provide or suggest accuracy or tolerances of the techniques described. Parameters such as search units, examination surface conditions, material composition, etc. can all have a bearing on the accuracy of results. It is recommended that users assess accuracy and tolerances applicable for each application. 1.3 This guide does not purport to provide instruction to measure flaw length. 1.4 This standard guide does not provide, suggest, or specify acceptance standards. After flaw-sizing evaluation has been made, the results should be applied to an appropriate code or standard that specifies acceptance criteria. 1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 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 requirements 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 practices referenced in this document are applicable to measuring the height of planar flaws open to the surface that originate on the far-surface or near-surface of the component. These practices are applicable to through-wall sizing of mechanical or thermal fatigue flaws, stress corrosion flaws, or any other surface-connected planar flaws. 5.2 The techniques outlined describe proven ultrasonic flaw sizing practices and their associated limitations, using refracted longitudinal wave and shear wave techniques as applied to ferritic or austenitic components. Other materials may be examined using this guide with appropriate standardization reference blocks. The practices described are applicable to both manual and automated examinations. 5.3 The techniques recommended in this standard guide use Time of Flight (TOF) or Delta Time of Flight (ΔTOF) methods to accurately measure the flaw size. This guide does not include the use of signal amplitude methods to determine flaw size. 5.4 Generally, with these sizing methods the volume of material (or component thickness) to be sized is divided into thirds; the inner 1 / 3 , the middle 1 / 3 and the near 1 / 3. Using the far-surface Creeping Wave Method the user can qualitatively segregate the flaw into the approximate 1 / 3 zone. 5.5 The sizing methods are used in 1 / 3 zones to quantitatively size the crack, that is, Tip-diffraction for the far 1 / 3 , Bi-Modal method for the middle 1 / 3 , and the Focused Longitudinal Wave or Focused Shear Wave Methods for the near 1 / 3 . These 1 / 3 zones are generally applicable to most sizing applications, however, the various sizing methods have applications outside these 1 / 3 zones provided a proper reference block and technique is demonstrated.