This specification covers uncoated, high-strength, hard-drawn steel wire for prestressed concrete tanks and similar structures. Steel samples shall be processed by either open-hearth, basic-oxygen, or electric furnace melting process. The wires shall be cold-drawn as well. Cast or heat analysis and product analysis shall be performed wherein the steel materials shall conform to the required chemical compositions of carbon, manganese, phosphorus, sulfur, and silicon. Steel specimens shall also undergo tensile tests, wrap tests, and torsion tests. Final products shall be marked by a tag.

1.1 This specification covers uncoated, high-strength, hard-drawn steel wire for use in the construction of prestressed concrete tanks and similar structures. In application, the wire is continuously wrapped on the structure maintaining tension by a device using a wire drawing die, or mechanical tensioning system without re-drawing.

1.2 This specification is applicable only to the condition of the wire as delivered to the purchaser. It is not applicable to the properties or condition of the wire after application.

1.2.1 Type A wire is to be tensioned by drawing through a wire drawing die or by a mechanical system without re-drawing.

1.2.2 Type B wire is drawn to finished diameter by the manufacturer for tensioning by a mechanical system without re-drawing.

Note 1: Type A wire, when tensioned by drawing through a die, may not function properly if the purchaser does not ensure that during application the surface of the wire is free of rust and foreign materials that can be detrimental to good wire drawing practice. Further, the purchaser should ensure that proper wire drawing techniques are followed, including adequate lubrication, cooling, and proper die mechanics.

1.3 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.

1.4 This specification is applicable for orders in either inch-pounds units (as Specification A821) or in SI units (as Specification A821M).

1.5 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 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.