1.1 本规范 2. 涵盖压力容器部件的淬火和回火碳钢和合金钢锻件的要求。 1.2 所有等级均视为在适当条件下可焊接。焊接技术至关重要，前提是焊接工艺和检查将符合所用材料等级的批准方法。 注1: 1级和1A级的化学成分不同，但机械要求相同。 注2: 名称变更如下: 现在的 从前 1级 1级 1A级 1A类 1C级 4级 二年级一班 2级 二年级二班 2A类 3年级1班 3级 3年级2班 3A级 4N级1级 7级 4N级2级 7A级 4N级3级 7B类 五年级一班 8级 5年级2班 8A级 11年级4班 11C级 22年级3班 22B级 22年级4班 22C级 22年级5班 22D级 22V级 22V级 3V级 3V级 1.3 以英寸-磅单位或国际单位制（公制）表示的数值应单独视为标准值。 在正文和表格中，国际单位制显示在括号中。每个系统中规定的值不一定是精确的等价物；因此，为确保符合本标准，每个系统应独立使用，且两个系统的值不得组合。 1.4 除非订单规定了适用的“M”规格名称，否则材料应以英寸-磅为单位提供。 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》中确立的国际公认标准化原则制定的。

1.1 This specification 2 covers requirements for quenched and tempered carbon and alloy steel forgings for pressure vessel components. 1.2 All grades are considered weldable under proper conditions. Welding technique is of fundamental importance, and it is presupposed that welding procedure and inspection will be in accordance with approved methods for the grade of material used. Note 1: Grades 1 and 1A have different chemistries but the same mechanical requirements. Note 2: Designations have been changed as follows: Current Formerly Grade 1 Class 1 Grade 1A Class 1A Grade 1C Class 4 Grade 2 Class 1 Class 2 Grade 2 Class 2 Class 2A Grade 3 Class 1 Class 3 Grade 3 Class 2 Class 3A Grade 4N Class 1 Class 7 Grade 4N Class 2 Class 7A Grade 4N Class 3 Class 7B Grade 5 Class 1 Class 8 Grade 5 Class 2 Class 8A Grade 11 Class 4 Class 11C Grade 22 Class 3 Class 22B Grade 22 Class 4 Class 22C Grade 22 Class 5 Class 22D Grade 22V Class 22V Grade 3V Class 3V 1.3 The values stated in either inch-pound units or SI (metric) units are to be regarded separately as standard. Within the text and tables, the SI units are shown in brackets. 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.