1.1 本规范涵盖25%的铁基耐热合金铸件 % 铬，12 % 镍级，用于电炉中的结构元件、容器和支架、石油蒸馏管支架以及2000年以前的类似应用 华氏度[1095度 °C]。 1.2 除第节规定的元素外，没有其他元素的重要比例 5. 通常，本规范涵盖的两种合金可区分如下: 1.2.1 I型- 在1500到2000之间的温度下具有相对较低极限蠕变应力的合金 °F[815和1095 °C]，并且在1300到1500之间的温度下短时间老化后，在常温下具有较高的延展性 °F[705和815 °C]。 1.2.2 II型- 具有较高极限蠕变应力的合金，但在1350至1500之间的温度下短时间时效时，在常温下可能会产生较低的延展性 °F[730和815 °C]。 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值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.3.1 在文本中，国际单位显示在括号中。 1.4 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》中确立的国际公认标准化原则制定的。

1.1 This specification covers iron-base, heat-resisting alloy castings of the 25 % chromium, 12 % nickel class, intended for structural elements, containers, and supports in electric furnaces, petroleum still tube supports, and for similar applications up to 2000 °F [1095 °C]. 1.2 In the absence of significant proportions of elements other than those prescribed in Section 5 , the two types of alloys covered by this specification may in general be distinguished as follows: 1.2.1 Type I— Alloys characterized by relatively low limiting creep stress at temperatures between 1500 and 2000 °F [815 and 1095 °C], and relatively high ductility at ordinary temperatures after aging for short periods at temperatures between 1300 and 1500 °F [705 and 815 °C]. 1.2.2 Type II— Alloys having relatively high limiting creep stress but which may develop low ductility at ordinary temperatures when aged for short periods at temperatures between 1350 and 1500 °F [730 and 815 °C]. 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 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.