1.1 本规范涵盖适用于通过渗氮进行表面硬化的合金钢棒材，指定为A、B、C和D级。A级和D级棒材为通用棒材；B级钢筋为自由加工钢筋；C级钢筋含有3.50 % 镍和具有较高的芯强度。所有等级通常为热轧、淬火和回火状态。然而，买方可指定任何类别的无心研磨或车削钢筋。此外，可根据本规范购买适合锻造的轧制、退火或未退火棒材。当提供轧制、退火或未退火钢筋时 6. , 10 和 11 不适用。 1.2 以英寸-磅单位表示的数值视为标准值。括号中给出的值是数学转换为SI单位，仅供参考，不被视为标准单位。 1.3 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 covers alloy steel bars, suitable for surface hardening by nitriding, designated as Classes A, B, C, and D. Class A and Class D bars are general-purpose bars; Class B bars are free-machining bars; Class C bars contain 3.50 % nickel and are characterized by higher core strength. All classes are normally furnished in the hot-rolled, quenched, and tempered condition. However, centerless-ground or turned bars, in any of the classes, may be specified by the purchaser. Also, as-rolled, annealed, or unannealed bars suitable for forging may be purchased to this specification. When as-rolled, annealed, or unannealed bars are furnished, Sections 6 , 10 , and 11 are not applicable. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 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.