Patent ID: 8308875

Claim:
A high-strength steel wire rod comprising a pearlite structure of an area ratio of 97% or greater not including 100% and a balance of non-pearlite structures including one or more of bainite, degenerate-pearlite and pro-eutectoid ferrite, and having a pearlite block size of not less than 20 μm and not greater than 45 μm, produced by a process comprising: hot rolling a steel billet comprising in mass %, C: 0.70 to 1.10%, Si: 0.1 to 1.5%, Mn: 0.1 to 1.0%, Al: 0.01% or less, Ti: 0.01% or less, N: 10 to 60 mass ppm, B: not less than (0.77×N (mass ppm)−17.4) mass ppm or 5 mass ppm, whichever is greater, and not greater than 52 mass ppm, and the balance of Fe and unavoidable impurities, coiling the hot-rolled steel in the temperature range between Tmin shown below and 950° C., subjecting the coiled steel to patenting using a cooling method in which a cooling rate between 800 to 600° C. is 5° C./s or greater, Tmin being 800° C. when B (mass ppm)−0.77×N(mass ppm)>0.0, and Tmin being Tmin =950+1450/(B (mass ppm)−0.77×N(mass ppm)−10)° C. when B(mass ppm)−0.77×N(mass ppm)≦0.0.