1.1 本规范涵盖各种结构、建筑、压力容器和耐热应用的马氏体不锈钢。这些钢的机械性能通常（但不一定）通过通常称为回火的适当热处理来发展。 1.2 本规范下的钢材有两个等级: 等级 屈服强度，最小值，ksi[MPa] 40 [275] 40 [275] 50 [345] 50 [345] 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；然而，目前的实践通常将根据本规范提供的板材的最大厚度限制为2英寸[50毫米]。 1.4 本规范以英寸磅单位和国际单位制表示；但是，除非采购订单或合同规定了适用的 M 规格名称（国际单位制），应采用英寸磅单位。以国际单位制或英寸磅单位表示的数值应单独视为标准。在正文中，国际单位制显示在括号中。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。将两个系统的值合并可能导致不符合标准。 1.5 提供了补充要求，供买方选择使用。只有当买方在采购订单或合同中单独规定时，补充要求才适用。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 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 martensitic stainless steels for various structural, architectural, pressure vessel, and heat-resisting applications. The mechanical properties of these steels are customarily, but not necessarily, developed by a suitable heat treatment generally referred to as tempering. 1.2 Steel products under this specification are available in two grades: Grade Yield Strength, min, ksi [MPa] 40 [275] 40 [275] 50 [345] 50 [345] 1.3 The maximum thickness of plates is limited only by the capacity of the composition to meet the specified mechanical property requirements; however, current practice normally limits the maximum thickness of plates furnished under this specification to 2 in. [50 mm]. 1.4 This specification is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract specifies the applicable M specification designation (SI units), the inch-pound units shall apply. The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. 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 Supplementary requirements are provided for use at the option of the purchaser. The supplementary requirements shall apply only when specified individually by the purchaser in the purchase order or contract. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 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.