1.1 本规程涵盖了通过浸入式超声波技术对矩形钢型材进行评级的程序。其目的是提供关于大夹杂物或小夹杂物簇含量的信息，以确定轴承应用钢批次的适用性。这种做法并没有以任何方式定义或确立可接受性的限制。 1.2 在本文件中，大型夹杂物在超声波术语中定义为反射面积等于或大于 1. / 64 在里面性能和厚度相似的钢对比试块中的直径平底孔。在金相学术语中，以这种方式定义的大夹杂物的尺寸与宏观试验方法显示的最小可检测尺寸大致相同 E45类 . 在某些情况下，根据其类型、化学成分、对超声波束的方向以及与试样声音进入表面的距离，可以单独或成群检测到比上述尺寸更小的夹杂物。 1.3 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。 1.4 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====== 6.1 与其他夹杂物评级方法的比较- 由于测试是在体积而非表面检查的基础上进行的，因此与涡流、磁粉、显微镜或宏观检查程序相比，超声波方法本质上能够更好地检测不经常出现的大夹杂物或小夹杂物簇。 6.2 夹杂物尺寸和类型的限制- 该方法的一个局限性是无法检测所有夹杂物。夹杂物化学、尺寸、形状、位置和分布可能会限制该方法提供不同于周围冶金结构产生的指示的能力。推荐规程仅适用于夹杂物尺寸和类型在该方法检测能力范围内的钢材检验。 对于夹杂物尺寸、分散度和化学成分无法通过超声波进行最佳夹杂物检测的钢，试验方法中详述了显微镜方法 E45类 可以应用。

1.1 This practice covers a procedure for the rating of rectangular steel sections by immersion ultrasonic techniques. Its purpose is to provide information on the content of large inclusions or clusters of small inclusions for determining the suitability of a steel lot for bearing applications. This practice in no manner defines or establishes limits of acceptability. 1.2 For this document, large inclusions are defined in ultrasonic terms as those having a reflecting area equivalent to or larger than a 1 / 64 in. diameter flat-bottom hole in a steel reference block of similar properties and thickness. In metallographic terms, large inclusions, defined in this way, are of approximately the same size as the smallest detectable sizes revealed by the macroscopic methods of Test Methods E45 . In some cases, inclusions smaller than those described previously can be detected either individually or in clusters, depending on their type, chemical composition, orientation to the ultrasonic beam and distance from the sound entry surface of the specimen. 1.3 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. 1.4 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 ====== 6.1 Comparison with Other Inclusion Rating Methods— Because the test is performed on a volumetric rather than a surface-examination basis, the ultrasonic method is inherently better able to detect infrequently occurring large inclusions or clusters of small inclusions than eddy current, magnetic particle, microscopical, or macroscopic examination procedures. 6.2 Limitation of Inclusion Size and Type— A limitation of the method is that it will not detect all inclusions. Inclusion chemistry, size, shape, location, and distribution may limit the ability of the method to provide indications distinct from those generated by the surrounding metallurgical structure. The recommended practice is only meaningfully applicable to examination of steel wherein the inclusion size and type are within the detection capabilities of the method. For steel wherein inclusion size, dispersion, and chemistry prevent optimum inclusion detection by ultrasonics, microscopical methods detailed in Test Methods E45 may be applied.