1.1 本规范涵盖了液压系统中使用的API I、II、III和IV类矿物油和合成油，其中性能要求需要具有以下特征之一的流体: 1.1.1 精制基础油或合成基础油（HH类）， 1.1.2 一种精炼矿物基础油或合成基础油，其具有防锈和氧化抑制剂（HL类）， 1.1.3 精炼矿物基础油或合成基础油，具有防锈和氧化抑制剂以及抗磨特性（HM级）， 1.1.4 精炼矿物基础油或合成基础油，具有防锈和氧化抑制剂、抗磨特性，粘度指数增加超过140（HV级）， 1.1.5 精炼矿物基础油或合成基础油，具有防锈和氧化抑制剂以及耐磨特性，满足比HM流体更高的性能水平，以满足更高要求的液压系统（HMHP级），以及 1.1.6 一种精制矿物基础油，具有防锈或合成基础油和氧化抑制剂，具有抗磨特性，粘度指数增加超过140，满足比高压流体更高的性能水平，以满足更高要求的液压系统（HVHP级）。 1.2 本规范规定了在进行充分维护时与大多数现有机械部件兼容的矿物油基或合成基液压流体的要求。 1.3 本规范仅定义在液压系统中安装新润滑油之前的润滑油。 1.4 本规范规定了液压油的具体类型。它不包括所有液压油。对于某些液压应用而言，未包含的某些机油可能令人满意。某些设备或使用条件可能允许或要求比本文所述的更宽或更窄范围的特性。 1.5 以国际单位制表示的数值应视为标准。本标准不包括其他计量单位。 1.5.1 例外情况-- 在里面 X1.3.9 在磨损保护方面，泵压力值以MPa为单位，括号中的psi是大部分行业立即认可的参考点。 1.6 以下安全隐患警告适用于本规范中引用的试验方法。 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。 1.7 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。

1.1 This specification covers mineral and synthetic oils of the types API groups I, II, III, and IV used in hydraulic systems, where the performance requirements demand fluids with one of the following characteristics: 1.1.1 A refined base oil or synthetic base stock (Class HH), 1.1.2 A refined mineral base oil or synthetic base stock with rust and oxidation inhibitors (Class HL), 1.1.3 A refined mineral base oil or synthetic base stock with rust and oxidation inhibitors plus anti-wear characteristics (Class HM), 1.1.4 A refined mineral base oil or synthetic base stock with rust and oxidation inhibitors, anti-wear characteristics, and increased viscosity index higher than 140 (Class HV), 1.1.5 A refined mineral base oil or synthetic base stock with rust and oxidation inhibitors plus anti-wear characteristics meeting a higher performance level than an HM fluid to address higher demanding hydraulic systems (Class HMHP), and 1.1.6 A refined mineral base oil with rust or synthetic base stock and oxidation inhibitors, anti-wear characteristics, and increased viscosity index higher than 140 meeting a higher performance level than an HV fluid to address higher demanding hydraulic systems (Class HVHP). 1.2 This specification defines the requirements of mineral oil-based or synthetic-based hydraulic fluids that are compatible with most existing machinery components when there is adequate maintenance. 1.3 This specification defines only new lubricating oils before they are installed in the hydraulic system. 1.4 This specification defines specific types of hydraulic oils. It does not include all hydraulic oils. Some oils that are not included may be satisfactory for certain hydraulic applications. Certain equipment or conditions of use may permit or require a wider or narrower range of characteristics than those described herein. 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 Exception— In X1.3.9 on Wear Protection, the values of pump pressure are in MPa, and the psi follows in brackets as a reference point immediately recognized by a large part of the industry. 1.6 The following safety hazard caveat pertains to the test methods referenced in this specification. 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. 1.7 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.