1.1 本规范 2. 涵盖适用于承压零件的正火和回火或淬火和回火条件下的低合金钢和马氏体不锈钢。本规范中各等级的可焊性从易焊性到仅在采取适当预防措施的情况下可焊性各不相同，在通过熔焊进行组装之前，应考虑每一等级的可焊接性。 1.2 选择将取决于设计、机械和使用条件。用户应注意，上述某些等级的淬透性可能会限制获得所需机械性能的最大尺寸。 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 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 low-alloy steels and martensitic stainless steels in the normalized and tempered, or quenched and tempered, condition suitable for pressure-containing parts. The weldability of the classes in this specification varies from readily weldable to weldable only with adequate precautions, and the weldability of each class should be considered prior to assembly by fusion welding. 1.2 Selection will depend on design, mechanical, and service conditions. Users should note that hardenability of some of the grades mentioned may restrict the maximum size at which the required mechanical properties are obtained. 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.