1.1 本规范 2 涵盖用于阀门、法兰、配件和其他承压零件的奥氏体钢铸件（ 附注1 ). 附注1: 规范涵盖了承压零件用碳钢铸件 A216/A216M 低合金钢铸件按规格 A217/A217M 和双相不锈钢铸件（按规格） A995/A995M . 1.2 本规范中包括许多等级的奥氏体钢铸件。由于这些等级在高温或腐蚀性环境中具有不同程度的适用性，因此买方有责任确定应提供哪种等级。选择将取决于设计和使用条件、机械性能以及耐高温或耐腐蚀特性，或两者兼而有之。1.2.1 由于热不稳定性，CE20N、CF3A、CF3MA和CF8A等级不建议在800°F[425°C]以上的温度下使用。 1.3 可选性质的补充要求由买方选择使用。只有当买方在采购订单或合同中单独规定时，补充要求才适用。 1.4 以SI单位或英寸-磅单位表示的值应单独视为标准值。每个系统中陈述的值可能不完全等同；因此，每个系统应独立使用。合并两个系统的值可能导致不符合标准。 1.4.1 本规范以英寸-磅单位和国际单位制单位表示；但是，除非采购订单或合同规定了适用的M-规格名称（SI单位），应适用英寸-磅单位。在正文中，SI单位显示在括号或圆括号中。 1.5 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《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 steel castings for valves, flanges, fittings, and other pressure-containing parts ( Note 1 ). Note 1: Carbon steel castings for pressure-containing parts are covered by Specification A216/A216M , low-alloy steel castings by Specification A217/A217M , and duplex stainless steel castings by Specification A995/A995M . 1.2 A number of grades of austenitic steel castings are included in this specification. Since these grades possess varying degrees of suitability for service at high temperatures or in corrosive environments, it is the responsibility of the purchaser to determine which grade shall be furnished. Selection will depend on design and service conditions, mechanical properties, and high-temperature or corrosion-resistant characteristics, or both. 1.2.1 Because of thermal instability, Grades CE20N, CF3A, CF3MA, and CF8A are not recommended for service at temperatures above 800 °F [425 °C]. 1.3 Supplementary requirements of an optional nature are provided for use at the option of the purchaser. The Supplementary requirements shall apply only when specified individually by the purchaser in the purchase order or contract. 1.4 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 non-conformance with the standard. 1.4.1 This specification is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract specifies the applicable M-specification designation (SI units), the inch-pound units shall apply. Within the text, the SI units are shown in brackets or parentheses. 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.