1.1 本规范涵盖了主要用于高温环境下焊接锅炉和压力容器的铬钼钨合金钢板。 1.2 根据本规范，板材有不同合金含量的等级，如下所示: 等级 名义 铬 含量，% 名义 钼 含量，% 名义 钨合金 含量，% 23 2.25 0.20 1.60 911 9 1 1 92 9 0.45 1.75 122 12 0.40 2 1.3 板材的最大厚度仅受成分满足规定机械性能要求的能力的限制。 1.4 本规范以英寸-磅单位和国际单位制表示。但是，除非订单规定了适用的“M”规格名称（国际单位制），否则材料应按英寸提供- 磅单位。 1.5 以国际单位制或英寸-磅单位表示的值应单独视为标准值。每个系统中所述的值可能不是完全等效的；因此，每个系统都应独立使用。将两个系统的值结合起来可能会导致不符合标准。 1.6 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 covers Chromium-Molybdenum-Tungsten alloy steel plates intended primarily for welded boilers and pressure vessels designed for elevated temperature service. 1.2 Plates are available under this specification in grades having different alloy contents as follows: Grade Nominal Chromium Content, % Nominal Molybdenum Content, % Nominal Tungsten Content, % 23 2.25 0.20 1.60 911 9.00 1.00 1.00 92 9.00 0.45 1.75 122 12.00 0.40 2.00 1.3 The maximum thickness of plates is limited only by the capacity of the composition to meet the specified mechanical property requirements. 1.4 The specification is expressed in both inch-pound units and in SI units. However, unless the order specifies the applicable “M” specification designation (SI units), the material shall be furnished to inch-pound units. 1.5 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. 1.6 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.