Patent ID: 7850793

Claim:
A hot-rolled wire rod obtained by hot rolling a steel composition comprising (in mass %): C: 0.6 to 1.0%, Si: 0.1 to 0.85%, Mn: 0.3 to 1.0%, Cr: 0.3% or less, excluding zero %, P: 0.01% or less, and S: 0.02% or less; performing a first cooling of the wire rod at an average cooling rate of 8 to 20° C./sec in a temperature range of from 900 to 670° C.; and performing a second cooling of the wire rod at an average cooling rate of 1 to 5° C./sec in a temperature range of from 670 to 500° C.; wherein said hot-rolled wire rod is 5.0 mm or more in diameter; not less than 90% of said wire rod in area percentage comprises a pearlite structure; a loading density (d/L) of said wire rod is controlled to be 0.20 or less when the wire rod is loaded on a loop conveyor during said first and second cooling, wherein d is the diameter of the wire rod and L is the ring pitch; and the mechanical properties of said wire rod 4 m in length satisfy the following expressions (1) to (4): (1) TS*−30≦Average value of tensile strength (TS AV in MPa)≦TS*+30, where, TS*=400×{[C]+([Mn]+[Si])/5}+670 and the elements in square brackets [ ] in the equation mean the contents of relevant elements in percentage, (2) Standard deviation of tensile strength (TSσ)≦30 MPa, (3) Average value of reduction of area (RA AV )>35%, (4) Standard deviation of reduction of area (RAσ)≦4%.