1.1 本规范规定了在螺栓、螺钉、双头螺栓和铆钉的制造和加工过程中可能出现的各种类型的表面不连续性的允许限值，包括热处理机器螺钉、自攻螺钉和sems（不包括螺旋垫圈组件的垫圈）。本规范涵盖公称直径为4 mm及以上、规定最小抗拉强度为420 MPa及以上的公制系列产品；和英寸系列产品，标称直径为5号（0.1250英寸）及以上，规定的最小抗拉强度为60 000psi或更高。 1.2 当应用的工程要求需要控制螺栓、螺钉、双头螺栓或铆钉的表面不连续性时，买方应规定是否符合ASTM规范 F788/F788M ，在原始询价和采购订单中。 1.2.1 当应用的工程要求要求将螺栓、螺钉、双头螺栓和铆钉的表面不连续性控制在比本规范规定的范围更近的范围内时，买方应在原始询价单和采购订单中规定适用的限制。 1.3 本规范中规定的标称直径为4至24 mm（含）的公制螺栓、螺钉和双头螺栓的允许限值与ISO中给出的要求基本相同 6157/I。对于任何英寸系列产品的表面不连续性或铆钉，都没有ISO标准。 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。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 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 establishes allowable limits for the various types of surface discontinuities that may occur during the manufacture and processing of bolts, screws, studs, and rivets including heat-treated machine screws, tapping screws, and sems (the washers of screw-washer assemblies are excluded). This specification covers metric series products with nominal diameters of 4 mm and larger and with specified minimum tensile strengths of 420 MPa and higher; and inch series products with nominal diameters of No. 5 (0.1250 in.) and larger and with specified minimum tensile strengths of 60 000 psi and higher. 1.2 When the engineering requirements of the application necessitate control of surface discontinuities on bolts, screws, studs, or rivets, the purchaser shall specify conformance to ASTM Specification F788/F788M , in the original inquiry and purchase order. 1.2.1 When the engineering requirements of the application necessitate that surface discontinuities on bolts, screws, studs, and rivets be controlled within limits closer than those specified in this specification, the purchaser shall specify the applicable limits in the original inquiry and purchase order. 1.3 The allowable limits established in this specification for metric bolts, screws, and studs with nominal diameters from 4 to 24 mm inclusive, are essentially identical with requirements given in ISO 6157/I. There are no ISO standards for surface discontinuities on any inch-series products, or for rivets. 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.