1.1 本规范涵盖预应力混凝土施工中使用的两种应力消除圆形高碳钢丝，如下所示: 1.1.1 BA型 钢丝用于冷端变形用于锚固（按钮锚固）的应用，以及 1.1.2 WA型 钢丝用于两端由楔块锚固，且不涉及钢丝的冷端变形（楔块锚固）。 1.2 当买方要求对产品进行低松弛钢丝和松弛试验时，提供了补充要求（S1）。补充要求仅在采购订单或合同中规定时适用。 1.3 本规范适用于英寸磅单位（如规范A421）或国际单位制（如规范A421M）的订单。 1.4 以英寸-磅或国际单位制表示的数值应单独视为标准值。在文本中，国际单位显示在括号中。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。合并两个系统的值可能会导致不符合规范。 1.5 本规范的文本参考了提供解释材料的注释和脚注。这些注释和脚注（不包括表中的注释和脚注）不应视为本规范的要求。 1.6 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 two types of stress-relieved round high-carbon steel wire used in prestressed concrete construction, as follows: 1.1.1 Type BA wire is used for applications in which cold-end deformation is used for anchoring purposes (Button Anchorage), and 1.1.2 Type WA wire is used for application in which the ends are anchored by wedges, and no cold-end deformation of the wire is involved (Wedge Anchorage). 1.2 A supplementary requirement (S1) is provided for use where low-relaxation wire and relaxation testing for that product is required by the purchaser. The supplementary requirement applies only when specified in the purchase order or contract. 1.3 This specification is applicable for orders in either inch-pounds units (as Specification A421) or in SI units (as Specification A421M). 1.4 The values stated in either inch-pound 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 specification. 1.5 The text of this specification references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables) shall not be considered as requirements of the specification. 1.6 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.