1.1 本试验方法是一种半定量微量方法，用于监测氧化试验期间润滑油中酸性成分的变化，此时润滑油的酸值在0.02范围内 mg至1.0 mg氢氧化钾/克样品。适用于汽轮机油、液压油和其他循环油。 注1: 此测试方法是测试方法的微观版本 D974 并且它产生类似于该方法的结果。 1.2 此测试方法设计用于样本量有限的情况。不得将其用作更高精度方法（如试验方法）的替代品 D974 或 D664 .不得将其用于监测在役油。 1.3 以国际单位制表示的数值应视为标准。 1.3.1 例外-- 括号中给出的值仅供参考。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者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。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ===意义和用途====== 5.1 本试验方法提供了通过实验室氧化试验获得的润滑油酸值的半定量估计，使用的样品量比试验方法少 D974 ， D664 或 D3339 .在《试验方法》中有具体应用 D943 和在测试方法中 D4871 因此，该试验方法提供了一种通过在不同时间间隔和不同氧化试验条件下测量酸值变化来监测润滑油相对氧化的方法。 5.2 由于该测试方法是半定量的，每个实验室应为每种氧化测试方法制定自己的标准，以确定何时从该半定量测试方法转换为更精确的酸值测试方法。

1.1 This test method is a semiquantitative micro method intended for monitoring the changes in acidic constituents occurring in lubricating oils during oxidation testing, when the acid number of such oils falls within the range from 0.02 mg to 1.0 mg of potassium hydroxide per gram of sample. It is applicable to such oils as turbine oils, hydraulic oils, and other circulating oils. Note 1: This test method is a micro version of Test Method D974 and it produces results similar to that method. 1.2 This test method is designed for use where sample size is limited. It shall not be used as a replacement for higher precision methods such as Test Methods D974 or D664 . It shall not be used to monitor oils in-service. 1.3 The values stated in SI units are to be regarded as the standard. 1.3.1 Exception— The values given in parentheses are for information only. 1.4 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. 1.5 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 This test method provides a semiquantitative estimate of the acid number of lubricating oils obtained from laboratory oxidation tests using smaller amounts of sample than Test Methods D974 , D664 , or D3339 . It has specific application in Test Method D943 and in Test Method D4871 . This test method, therefore, provides a means of monitoring the relative oxidation of lubricating oils by measuring changes in acid number, at different time intervals and under various oxidizing test conditions. 5.2 Since this test method is semiquantitative, each laboratory shall develop its own criteria for each oxidation test method for determining when to switch from this semiquantitative test method to a more precise test method for acid number.