STEEL WIRE ROD FOR HIGH-STRENGTH SPRING HAVING EXCELLENT DRAWABILITY INTO WIRE AND EXCELLENT POST-DRAWING BENDABILITY, PROCESS FOR MANUFACTURING SAME, HIGH-STRENGTH SPRING, AND PRODUCTION PROCESS THEREFOR

摘要

To provide a steel wire rod which exhibits excellent wire drawability and excellent post-drawing bendability. This steel wire rod for a high-strength spring contains 0.5 to 0.8% of C, 1.5 to 2.5% of Si, 0.5 to 1.5% of Mn, 0.05 to 0.5% of Ni, 0.05 to 2.5% of Cr, 0.05 to 0.5% of V with the balance being iron and unavoidable impurities, wherein: the area fraction of pearlite is 95% or more relative to the whole structure; the tensile strength (TS) and the reduction of area (RA) satisfy the relationship (1) [TS ≤ 1250MPa and RA ≥ 35%]; the standard deviation (TSσ) of tensile strength and the standard deviation (RAσ) of reduction of area satisfy the relationship (2) [TSσ ≤ 55.0 and RAσ ≤ 6.0]; and the area fraction of perlite having an interlamellar spacing of 0.9μm or more is 20% or less as observed at a position of d × 1/4, d being the diameter of the steel wire rod.