1.1 本规范 2. 涵盖淬火和回火条件下使用的镍铬钼合金钢板，用于制造焊接压力容器和其他压力设备。这些合金成分通常用于涉及2英寸板厚的结构。[50毫米]或更大。 1.2 本规范下的材料有两种类型，B和C。材料也有以下三类: 班 最小抗拉强度，ksi[MPa] 1. 105 [725] 2. 115 [795] 3. 90 [620] 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 最小板厚为 3. / 16 在里面[5毫米]。 1.5 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。 1.6 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一定是精确的等价物；因此，每个系统应相互独立使用。合并两个系统的值可能会导致不符合规范。 1.7 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 nickel-chromium-molybdenum alloy steel plates for use in the quenched and tempered condition, intended for the fabrication of welded pressure vessels and other pressure equipment. These alloy compositions are normally considered for construction involving plate thicknesses of 2 in. [50 mm] or greater. 1.2 Material under this specification is available in two types, B and C. The material is also available in three classes as follows: Class Minimum Tensile Strength, ksi [MPa] 1 105 [725] 2 115 [795] 3 90 [620] 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 plate thickness is 3 / 16 in. [5 mm]. 1.5 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. 1.6 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 necessarily 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 specification. 1.7 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.