1.1 本规范 2. 涵盖锅炉、压力容器和相关设备的四个等级的碳钢锻件。 注1: 名称更改如下: 现在的 从前 一年级 1级 二年级 2级 三年级 3级 四年级 4级 1.2 当需要额外的测试或检查时，提供了补充要求。只有当买方在订单中单独规定时，这些规定才适用。 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不一定是完全相等的；因此，为了确保符合标准，每个系统应独立使用，并且不得将两个系统的值组合使用。 1.4 除非订单规定了适用的“M”规格名称，否则材料应按英寸提供- 磅单位。 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 four grades of carbon steel forgings for boilers, pressure vessels, and associated equipment. Note 1: Designations have been changed as follows: Current Formerly Grade 1 Class 1 Grade 2 Class 2 Grade 3 Class 3 Grade 4 Class 4 1.2 Supplementary requirements are provided for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order. 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 are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. 1.4 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units. 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.