This standard covers the requirements for the manufacture, supply, and testing of plain, cold-drawn, stress-relieved steel wire used in prestressed concrete. It defines the necessary chemical composition limits, mechanical properties (such as tensile strength and proof stress), and mandatory tests like the relaxation and reverse bend tests to ensure wire ductility and strength.
plain hard-drawn steel wire for prestressed concrete, Part 1: Cold-drawn stress-relieved wire
Quick Reference Values
max carbon content0.85%
max sulphur content0.050%
max phosphorus content0.050%
min proof stress85% of specified minimum tensile strength
max relaxation at 1000 hrs5% (at 70% initial stress)
elongation at ruptureMinimum 4% on a gauge length of 200 mm
Practical Notes
Prestressing steel wires must be stored in extremely dry conditions and protected from ground contact to prevent pitting corrosion, which severely limits fatigue life.
Welding, heating, or brazing of the wire at the construction site is strictly prohibited as it destroys the high-tensile properties achieved through cold drawing.
Care should be taken during handling to prevent mechanical damage such as notching or severe bending, which act as stress concentrators.