1.1 本规范 2. 涵盖D-2M型1级和2级奥氏体球墨铸铁，用于压缩机、膨胀机、泵、阀门和其他主要用于低温服务的承压部件。 1.2 这些等级的奥氏体球墨铸铁的特征在于其石墨基本上呈球状且不含片状石墨。它们基本上不含碳化物，并含有足够的合金含量，以产生稳定的奥氏体基体，低至−423 °F[-252 °C]（液氢）。 1.3 以国际单位制或英寸磅单位表示的数值应单独视为标准。每个系统中规定的值可能不是完全相等的；因此，每个系统应独立使用。将两个系统的值结合起来可能会导致不符合标准。 1.3.1 在正文中，国际单位制显示在括号中。 1.4 以下注意事项仅适用于测试方法部分，第节 11 ，本规范: 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。

1.1 This specification 2 covers austenitic ductile iron, Type D-2M, Classes 1 and 2, for compressors, expanders, pumps, valves, and other pressure-containing parts intended primarily for low-temperature service. 1.2 These grades of austenitic ductile iron are characterized by having their graphite substantially in a spheroidal form and free of flake graphite. They are essentially free of carbides and contain sufficient alloy content to produce a stable austenitic matrix down to −423 °F [−252 °C] (liquid hydrogen). 1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.3.1 Within the text, the SI units are shown in brackets. 1.4 The following precautionary caveat pertains only to the test methods portion, Section 11 , of 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. 1.5 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.