1.1 本规范 2. 涵盖两种类型的2 1. / 4. 淬火和回火条件下使用的Cr-1 Mo和三种Cr-Mo-V合金钢板，用于制造焊接压力容器和部件。 1.2 本规范下的材料有五种类型，分别为“A”、“B”、“C”、“D”和“E”。除了碳、磷、硫和镍的限制性限制外，B型与A型相同。该材料也可分为五类，强度等级如下。E型仅适用于4级和4a级。 班 最小抗拉强度，ksi[MPa] 1. 105 [725] 2. 115 [795] 3. 95 [655] 4和4a 85 [585] 1.3 板材的最大厚度仅受化学成分满足规定机械性能要求的能力的限制。 1.4 板的最小厚度限于 3. / 16 在里面[5毫米]。 1.5 该材料适用于熔焊。焊接技术至关重要，前提是焊接程序将符合批准的方法。 1.6 轧制状态下的这些合金钢板在火焰切割、运输和搬运过程中容易开裂。只有在制造商和买方或制造商相互同意的情况下，才应在轧制状态下装运。 1.7 以英寸-磅单位或国际单位表示的数值应单独视为标准值。在文本中，国际单位显示在括号中。 每个系统中规定的值不是精确的等效值，因此，每个系统必须独立于其他系统使用。合并两个系统的值可能会导致不符合本规范。 1.8 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 two types of 2 1 / 4 Cr-1 Mo and three types of Cr-Mo-V alloy steel plates for use in the quenched-and-tempered condition, intended for the fabrication of welded pressure vessels and components. 1.2 Material under this specification is available in five types, designated “A,” “B,” “C,” “D,” and “E.” Type B is identical to Type A except for restrictive limits for carbon, phosphorus, sulfur, and nickel. The material is also available in five classes having the following strength levels. Type E is available only as Class 4 and 4a. Class Minimum Tensile Strength, ksi [MPa] 1 105 [725] 2 115 [795] 3 95 [655] 4 and 4a 85 [585] 1.3 The maximum thickness of plates is limited only by the capacity of the chemical composition to meet the specified mechanical property requirements. 1.4 The minimum thickness of plates is limited to 3 / 16 in. [5 mm]. 1.5 The material is intended to be suitable for fusion welding. Welding technique is of fundamental importance and it is presupposed that welding procedures will be in accordance with approved methods. 1.6 These alloy steel plates in the as-rolled condition are sensitive to cracking during flame cutting, transit, and handling. They should be shipped in the as-rolled condition only with the mutual agreement of the manufacturer and the purchaser or fabricator. 1.7 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents, therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with this specification. 1.8 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.