1.1 本规范 2. 涵盖阀门、法兰、配件和其他承压零件的马氏体不锈钢和合金钢铸件( 注1 )主要用于高温和腐蚀性环境( 注释2 ). 1.2 涵盖一级马氏体不锈钢和九级铁素体合金钢。选择将取决于设计和使用条件、机械性能以及高温和耐腐蚀特性( 附注3 ). 注1: 本规范涵盖承压部件用碳钢铸件 A216/A216M . 与规范相当的低合金淬火和回火等级 A217/A217M 等级可在两种规格中找到 A352/A352M 和 A487/A487M . 注2: 本规范涵盖的等级代表通常适用于通过熔焊与其他铸件或锻钢零件组装的材料。 这并不意味着这些等级具有同等的可焊性；因此，买方有责任自行制定合适的焊接技术。由于这些等级对高温和耐腐蚀服务具有不同程度的适用性，买方还应负责确定应提供的等级，并适当考虑适用施工规范的要求。 注3: 制定本规范的委员会包括九个等级的材料，这些材料被认为代表了适用于阀门、法兰、配件和其他承压零件的铁素体合金钢的基本类型。当需求变得明显时，委员会将考虑将可能更好地满足某些类型服务的其他合金钢纳入本规范。 1.3 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。 1.4 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 martensitic stainless steel and alloy steel castings for valves, flanges, fittings, and other pressure-containing parts ( Note 1 ) intended primarily for high-temperature and corrosive service ( Note 2 ). 1.2 One grade of martensitic stainless steel and nine grades of ferritic alloy steel are covered. Selection will depend on design and service conditions, mechanical properties, and the high-temperature and corrosion-resistant characteristics ( Note 3 ). Note 1: Carbon steel castings for pressure-containing parts are covered by Specification A216/A216M . Low alloy quench-and-tempered grades equivalent to Specification A217/A217M grades may be found in both Specifications A352/A352M and A487/A487M . Note 2: The grades covered by this specification represent materials that are generally suitable for assembly with other castings or wrought steel parts by fusion welding. It is not intended to imply that these grades possess equal degrees of weldability; therefore, it is the responsibility of the purchaser to establish for himself a suitable welding technique. Since these grades possess varying degrees of suitability for high-temperature and corrosion-resistant service, it is also the responsibility of the purchaser to determine which grade shall be furnished, due consideration being given to the requirements of the applicable construction codes. Note 3: The committee formulating this specification has included nine grades of materials that are considered to represent basic types of ferritic alloy steels suitable for valves, flanges, fittings, and other pressure-containing parts. Additional alloy steels that may better fulfill certain types of service will be considered for inclusion in this specification by the committee as the need becomes apparent. 1.3 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 nonconformance with the standard. 1.4 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.