Determine about the Hard-drawn steel wires

Hard-drawn steel wires which are indented or crimped are preferred for pre-tensioned members as their bond characteristics are superior to the plain wires. Strands normally comprise two, three or seven wires of 2 to 5 mm size. The helical form of  twisted wires in the strand improves the bond strength. Two and three-ply strands are made up of 2 mm and 3 mm diameter wires while a seven-ply strand is made by  twisting 2 to 5 mm wires.