1.1 本试验方法包括使用铬的X射线衍射峰的综合强度（峰下面积高于背景）测定钢中的残余奥氏体相 K α 或钼 K α X射线辐射。 1.2 该方法适用于铁素体相和奥氏体相的近随机结晶取向的碳钢和合金钢。 1.3 本试验方法适用于1 % 以体积计及以上。 1.4 如果可能，应从铁素体和奥氏体峰值强度中消除来自其他晶相（如碳化物）的X射线衍射峰干扰。 1.5 钢中的大量合金含量会导致峰值强度发生一些变化，而这种变化在本方法中并未考虑。该方法在总合金含量超过15重量的钢中的应用 % 应小心操作。如有必要，用户可以计算理论修正系数，以说明化学成分变化导致的奥氏体和铁素体晶胞体积的变化。 1.6 单位- 以英寸-磅单位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。 1.7 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。 1.8 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====== 2. 1. 重要性- 在中等（0.40重量）的热处理低合金高强度钢的微观结构中发现了具有近似随机结晶取向的残余奥氏体 %) 或更高的碳含量。虽然残余奥氏体在微观结构中可能不明显，并且可能不会影响钢的整体机械财产，例如硬度，但在使用期间，残余奥氏体转变为马氏体会影响钢的性能。 2.2 使用- 残余奥氏体的测量可纳入低合金钢开发计划，以确定其对机械财产的影响。作为质量控制实践的一部分，残余奥氏体可在热处理批次钢中包含的配对试样或试验段上进行测量。在材料性能的研究中，可以包括对钢中的残余奥氏体的测量。

1.1 This test method covers the determination of retained austenite phase in steel using integrated intensities (area under peak above background) of X-ray diffraction peaks using chromium K α or molybdenum K α X-radiation. 1.2 The method applies to carbon and alloy steels with near random crystallographic orientations of both ferrite and austenite phases. 1.3 This test method is valid for retained austenite contents from 1 % by volume and above. 1.4 If possible, X-ray diffraction peak interference from other crystalline phases such as carbides should be eliminated from the ferrite and austenite peak intensities. 1.5 Substantial alloy contents in steel cause some change in peak intensities which have not been considered in this method. Application of this method to steels with total alloy contents exceeding 15 weight % should be done with care. If necessary, the users can calculate the theoretical correction factors to account for changes in volume of the unit cells for austenite and ferrite resulting from variations in chemical composition. 1.6 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. 1.7 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. 1.8 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 ====== 2.1 Significance— Retained austenite with a near random crystallographic orientation is found in the microstructure of heat-treated low-alloy, high-strength steels that have medium (0.40 weight %) or higher carbon contents. Although the presence of retained austenite may not be evident in the microstructure, and may not affect the bulk mechanical properties such as hardness of the steel, the transformation of retained austenite to martensite during service can affect the performance of the steel. 2.2 Use— The measurement of retained austenite can be included in low-alloy steel development programs to determine its effect on mechanical properties. Retained austenite can be measured on a companion specimen or test section that is included in a heat-treated lot of steel as part of a quality control practice. The measurement of retained austenite in steels from service can be included in studies of material performance.