STEEL WIRE ROD WITH EXCELLENT SPRING WORKABILITY FOR HIGH-STRENGTH SPRING, PROCESS FOR MANUFACTURING SAME, AND HIGH-STRENGTH SPRING

摘要

This steel wire rod for a high-strength spring is a hot-rolled steel wire rod having both a prescribed chemical composition and a structure which has a pearlite area fraction of 90% or more and in which the average (Pave) of grain size numbers of pearlite nodules and the standard deviation (Psigma) thereof satisfy relationships (1) and (2) respectively. 8.0 <= Pave <= 12.0 ··· (1) 0.0 < Psigma <= 0.5 ··· (2)