AASHTO M 203:2012(R2016) Standard Specification for Steel Strand, Uncoated Seven-Wire for Concrete Reinforcement.
This specification covers two types and two grades of steel strand, uncoated seven-wire for use in pretensioned and post-tensioned prestressed concrete construction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation strand shall be regarded as the standard type. Stress-relieved (normal-relaxation) strand will not be furnished unless specifically ordered or by arrangement between purchaser and supplier. Grade 1725  and Grade 1860  have minimum ultimate strengths of 1725 MPa [250 ksi] and 1860 MPa [270 ksi], respectively, based on the nominal area of the strand.
The values stated in either inch-pound units or SI units are to be regarded as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.
The supplementary requirements in S I shall be specified tbr 15.24-mm- [0.600-in.-] diameter uncoated seven-wire steel strand if needed fbr applications in prestressed ground anchors.
• T 244, Mechanical Testing of Steel Products
2.2. ASTM Standards:
• A981 /A981 M, Standard Test Method for Evaluating Bond Strength for 0.600-in.[15.24-mm] Diameter Steel Prestressing Strand. Grade 270 , Uncoatcd, Used in Prestressed Ground Anchors
• E328, Standard Test Methods for Stress Relaxation Tests for Materials and Structures
2.3. IEEE/ASTM Standard:
• SI 10. American National Standard for Use of the International System of Units (SI):
The Modern Metric System
2.4. Military Standards:
• MIL-STD-l29, Marking for Shipment and Storage
• MIL-STD-163, Steel Mill Products Preparation for Shipment and Storage
MATERIALS AND MANUFACTURE
Base Metal—The base metal shall be carbon steel of such quality that when drawn to wire, fabricated into strand, and then thermally treated, it shall have the properties and characteristics prescribed in this specification.
5.2. Wire—The wire from which the strand is to be fabricated shall be round and have a dry-drawn finish.
Note 2—This product is a composite of seven wires and is produced to mechanical properties only; the chemical composition of’ all wires or any individual wire is not pertinent to this application, and heat identity is not necessarily maintained. It is possible that wire from more than one heat may be used in the manufacture of a reel or pack. Traceability is based on pack identity as maintained and reported by the manufacturer.
5.3. Trc’c,gme,it—Afler stranding, low-relaxation strand shall be subjected to a continuous thermalmechanical treatment to produce the prescribed mechanical properties.AASHTO M 203 pdf download.