1.1 本规范 2. 第8页和第9页 % 低温焊接压力容器用镍合金钢锻造或轧制法兰、配件、阀门和零件。本规范适用于最大截面厚度为3英寸的锻件。[75 mm]，在双重正火和回火条件下，5 in。在淬火和回火条件下为[125 mm]。本规范下的锻件用于工作温度不低于−320华氏度[−196°C]对于I型或−275华氏度[−II型为170°C]或高于250°F[121°C]。 1.2 本规范下的材料有两种类型，具有不同的化学成分，如下所示: 类型 标称镍含量， % 我 二、 9 8. 1.3 本规范以英寸-磅单位和国际单位表示。但是，除非订单规定了适用的“M”规格名称（国际单位制），否则材料应以英寸-磅为单位。 1.4 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，SI单位显示在括号中。每个系统中规定的值可能不完全相等；因此，每个系统应独立于其他系统使用。结合两个系统的值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 8 and 9 % nickel-alloy steel forged or rolled flanges, fittings, valves, and parts intended for use in welded pressure vessels for low-temperature service. The specification is applicable to forgings with maximum section thickness of 3 in. [75 mm] in the double normalized and tempered condition and 5 in. [125 mm] in the quenched and tempered condition. Forgings under this specification are intended for service at operating temperatures not lower than −320 °F [−196 °C] for Type I or −275 °F [−170 °C] for Type II or higher than 250 °F [121 °C]. 1.2 Material under this specification is available in two types having different chemical compositions as follows: Type Nominal Nickel Content, % I II 9 8 1.3 This specification is expressed in both inch-pound units and SI units. However, unless the order specifies the applicable “M” specification designation (SI units), the material shall be furnished to inch-pound units. 1.4 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 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.