1.1 本试验方法包括使用具有适当扭矩范围和特定主轴的旋转粘度计来测定自动变速器油、齿轮油、液压油和某些润滑剂的低剪切率粘度。该测试方法的粘度范围为300 mPa·s至900 000 mPa·s 1.2 该测试方法以前被称为“通过Brookfield粘度计测量的润滑剂的低温粘度”。在润滑剂行业， D2983 测试结果通常被称为“布鲁克菲尔德 2. 粘度”，这意味着通过该方法确定的粘度。 1.3 本试验方法包括四个步骤:当仅使用空气浴冷却样品以准备粘度测量时，使用步骤A。 当使用机械冷却的可编程液体浴来冷却样品以准备粘度测量时，使用程序B。当使用机械制冷恒温液浴通过模拟空气池（SimAir）冷却样品时，使用程序C 3. 为粘度测量做准备的细胞。程序D通过利用热电加热和冷却温度控制的样品室以及可编程旋转粘度计，自动测定低温、低剪切率粘度。 1.4 这种测试方法有多种精度研究。 1.4.1 用于程序A、B和C精密度研究的粘度数据范围为300 mPa·s至170 000 mPa·s，试验温度为–12 °C，-26 °C和-40 °C。 附录X5 包括–55的精度数据 °C试验温度，包括粘度大于500的样品 000 mPa·s。 1.4.2 用于程序D精密度研究的粘度数据来自6400 mPa·s至256 000 mPa·s，试验温度为-26 °C和-40 °C。 1.5 以国际单位制表示的数值应视为标准。本标准中不包括其他计量单位。 1.5.1 本试验方法使用国际单位制单位，毫帕秒（mPa·s）作为粘度单位。（1 cP=1 mPa·s）。 1.6 警告 --汞已被许多监管机构指定为一种可能导致严重医疗问题的危险物质。汞或其蒸汽已被证明对健康有害，对材料具有腐蚀性。 处理汞和含汞产品时要小心。有关更多信息，请参阅适用的产品安全数据表（SDS）。当地或国家法律有可能禁止销售含汞或含汞产品，或两者兼有。用户必须确定在其所在地销售的合法性。 1.7 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。 1.8 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 自动变速器油、齿轮油、扭矩和拖拉机油以及工业和汽车液压油的低温低剪切率粘度（请参阅 附录X4 )对于许多机械装置的正确操作具有相当重要的意义。这些油和流体在低温下的粘度特性的测量通常用于指定其使用验收。该测试方法用于许多规范中。 5.2 最初，开发该测试方法是为了确定自动变速器油液（ATF）是否符合最初使用特定型号粘度计定义的OEM低温性能标准。 6. 7. 最初的ATF性能相关性研究中涵盖的粘度范围小于1000 mPa·s至60以上 000 mPa·s。随着时间的推移，ATF相关性的成功和该测试方法的发展已应用于其他流体和润滑剂，如齿轮油、液压油等。 5.3 该试验方法的程序A、B、C和D描述了如何直接测量表观粘度，而不会出现与早期技术相关的误差，这些技术外推了在较高温度下获得的实验粘度数据。 注1: 通过油的插值或外推获得的低温粘度值可能会因凝胶化和其他形式的非- 牛顿对主轴速度和扭矩的响应。 5.4 程序A、B、C和D；如果粘度测量难以稳定，或者在5 s到10 主轴旋转开始后的s，且测量值稳定在60 s和180 s、 那么这很可能表明流体中与时间相关的结构破坏。一些配制的流体类型在一定的低温下或低于一定的低温时可能形成蜡结构，该低温在流体之间变化。粘度计的旋转轴会随着时间的推移使这种结构退化，导致在较长的测量时间内表观粘度降低。 这可能会掩盖较高的初始粘度。这种高初始粘度可能对某些机械有害，正如历史上在一些自动变速器中看到的那样。这就是开发这个测试的原因。 6. 7. 如果观察到这种现象，建议仔细考虑这种液体对应用的适用性。如果需要，测试方法 D5133 或测试方法 D6821 可以用来研究这些流体的行为。

1.1 This test method covers the use of rotational viscometers with an appropriate torque range and specific spindle for the determination of the low-shear-rate viscosity of automatic transmission fluids, gear oils, hydraulic fluids, and some lubricants. This test method covers the viscosity range of 300 mPa·s to 900 000 mPa·s 1.2 This test method was previously titled “Low-Temperature Viscosity of Lubricants Measured by Brookfield Viscometer.” In the lubricant industry, D2983 test results have often been referred to as “Brookfield 2 Viscosity” which implies a viscosity determined by this method. 1.3 This test method contains four procedures: Procedure A is used when only an air bath is used to cool samples in preparation for viscosity measurement. Procedure B is used when a mechanically refrigerated programmable liquid bath is used to cool samples in preparation for viscosity measurement. Procedure C is used when a mechanically refrigerated constant temperature liquid bath is used to cool samples by means of a simulated air cell (SimAir) 3 Cell in preparation for viscosity measurement. Procedure D automates the determination of low temperature, low-shear-rate viscosity by utilizing a thermoelectrically heated and cooled temperature-controlled sample chamber along with a programmable rotational viscometer. 1.4 There are multiple precision studies for this test method. 1.4.1 The viscosity data used for the precision studies for Procedures A, B, and C covered a range from 300 mPa·s to 170 000 mPa·s at test temperatures of –12 °C, –26 °C, and –40 °C. Appendix X5 includes precision data for –55 °C test temperature and includes samples with viscosities greater 500 000 mPa·s. 1.4.2 The viscosity data used for Procedure D precision study was from 6400 mPa·s to 256 000 mPa·s at test temperatures of –26 °C and –40 °C. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5.1 The test method uses the SI unit, milliPascal-second (mPa·s), as the unit of viscosity. (1 cP = 1 mPa·s). 1.6 WARNING —Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use Caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location. 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 ====== 5.1 The low-temperature, low-shear-rate viscosity of automatic transmission fluids, gear oils, torque and tractor fluids, and industrial and automotive hydraulic oils (see Appendix X4 ) are of considerable importance to the proper operation of many mechanical devices. Measurement of the viscometric properties of these oils and fluids at low temperatures is often used to specify their acceptance for service. This test method is used in a number of specifications. 5.2 Initially this test method was developed to determine whether an automatic transmission fluid (ATF) would meet OEM low temperature performance criterion originally defined using a particular model viscometer. 6, 7 The viscosity range covered in the original ATF performance correlation studies was from less than 1000 mPa·s to more than 60 000 mPa·s. The success of the ATF correlation and the development of this test method has over time been applied to other fluids and lubricants such as gear oils, hydraulic fluids, and so forth. 5.3 Procedures A, B, C, and D of this test method describe how to measure apparent viscosity directly without the errors associated with earlier techniques that extrapolated experimental viscometric data obtained at higher temperatures. Note 1: Low temperature viscosity values obtained by either interpolation or extrapolation of oils may be subject to errors caused by gelation and other forms of non-Newtonian response to spindle speed and torque. 5.4 Procedures A, B, C, and D; If viscosity measurements are difficult to stabilize or a noticeable decrease in viscosity is seen at a constant speed between an initial measurement made during the 5 s to 10 s after the spindle rotation commences and the stabilized measurement between 60 s and 180 s, then this most likely indicates time-dependent, structural breakdown in the fluid. Some formulated fluid types may form wax structures when soaked at or below a certain low temperature which varies among fluids. The rotating spindle of the viscometer can degrade this structure over time, resulting in a decrease in the apparent viscosity at longer measurement times. This can obscure a higher initial viscosity. It is possible that this high initial viscosity may be detrimental to certain machinery, as historically seen in some automatic transmissions. It was the reason for developing this test. 6, 7 It is recommended, that if this phenomenon is observed, the suitability of this fluid for the application is carefully considered. If desired, Test Method D5133 or Test Method D6821 may be used to study the behavior of these fluids.