1.1 本规范 2. 涵盖了两个等级的碳钢螺栓和螺柱的化学和机械要求 1. / 4. 在里面至4英寸。紧固件由表示抗拉强度和预期用途的“等级”指定，如下所示: 等级 描述 A级 用于一般应用的最小抗拉强度为60 ksi的螺栓、螺柱和螺杆， B级 螺栓、螺柱和螺杆 A. 抗拉强度为60至100 ksi，用于带有铸铁法兰的管道系统中的法兰接头，以及 C级 由规范取代 F1554 第36组 1.2 本规范不包括机器螺钉、螺纹切割/成型螺钉、机械膨胀锚或类似外螺纹紧固件的要求。 1.3 规范中涵盖了合适的螺母 A563型 . 除非另有规定，否则所有表面处理的每个紧固件等级的螺母等级和样式应如下所示: 紧固件等级和尺寸 螺母等级和样式 A. A. 1. / 4. 至1 1. / 2. 在里面 A、 十六进制 A大于1 1. / 2. 至4英寸。 A、 重型六角 B 1. / 4. 至4英寸。 A、 重型六角 1.4 以英寸-磅为单位的数值应视为标准值。本标准不包括其他计量单位。 1.5 提供了可选的补充要求S1，描述了焊接螺栓时应用的附加限制。仅在询价单、订单和合同中规定时适用。 1.6 本规范中使用的术语在术语中定义 F1789 除非本文另有规定。 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 the chemical and mechanical requirements of two grades of carbon steel bolts and studs in sizes 1 / 4 in. through 4 in. The fasteners are designated by “Grade” denoting tensile strength and intended use, as follows: Grade Description Grade A Bolts, studs, and threaded rod having a minimum tensile strength of 60 ksi and intended for general applications, Grade B Bolts, studs, and threaded rod A having a tensile strength of 60 to 100 ksi and intended for flanged joints in piping systems with cast iron flanges, and Grade C Replaced by Specification F1554 Gr.36 1.2 This specification does not cover requirements for machine screws, thread cutting/forming screws, mechanical expansion anchors or similar externally threaded fasteners. 1.3 Suitable nuts are covered in Specification A563 . Unless otherwise specified, the grade and style of nut for each grade of fastener, of all surface finishes, shall be as follows: Fastener Grade and Size Nut Grade and Style A A 1 / 4 to 1 1 / 2 in. A, hex A over 1 1 / 2 to 4 in. A, heavy hex B, 1 / 4 to 4 in. A, heavy hex 1.4 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 Supplementary Requirement S1 of an optional nature is provided, which describes additional restrictions to be applied when bolts are to be welded. It shall apply only when specified in the inquiry, order, and contract. 1.6 Terms used in this specification are defined in Terminology F1789 unless otherwise defined herein. 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.