1.1 本规范 2. 涵盖用于中低温环境下焊接压力容器的热处理碳锰硅钢板。 1.2 本规范下的材料有四种强度等级，即75 ksi[515 MPa]、85 ksi[585 MPa]、80 ksi[550 MPa]和90 ksi[620 MPa]最小极限抗拉强度。 1.3 A、B和C级板材的最大厚度仅受化学成分和热处理能力的限制，以满足规定的机械性能要求；然而，目前的做法通常将根据本规范提供的板材的最大厚度限制为6英寸。[150 mm]对于A级，4英寸。B级为[100 mm]，6 in。 [150 mm]对于C级。最大允许标称厚度为1.5 in。D级和2英寸的[40 mm]。E级为[50 mm]。 1.4 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 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 heat-treated carbon-manganese-silicon steel plates intended for use in welded pressure vessels at moderate and lower temperature service. 1.2 Material under this specification is available in four strength levels, 75 ksi [515 MPa], 85 ksi [585 MPa], 80 ksi [550 MPa], and 90 ksi [620 MPa] minimum ultimate tensile strengths. 1.3 The maximum thickness of plates for Grades A, B, and C is limited only by the capacity of the chemical composition and heat treatment to meet the specified mechanical property requirements; however, current practice normally limits the maximum thickness of plates furnished under this specification to 6 in. [150 mm] for Grade A, 4 in. [100 mm] for Grade B, and 6 in. [150 mm] for Grade C. The maximum permitted nominal thickness is 1.5 in. [40 mm] for Grade D and 2 in. [50 mm] for Grade E. 1.4 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. 1.5 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.