Patent ID: 8007716

Claim:
A steel wire for a high-strength spring having superior workability, the steel wire comprising tempered martensite, and comprising by mass: C: 0.53 to 0.68%; Si: 1.2 to 2.5%; Mn: 0.2 to 1.5%; Cr: 1.4 to 2.5%; Al: 0.05% or less, excluding 0%; at least one member selected from the group consisting of Ni: 0.4% or less, excluding 0%; V: 0.4% or less, excluding 0%; Mo: 0.05 to 0.5%; and Nb: 0.05 to 0.5%; and a remainder consisting essentially of Fe and inevitable impurities; wherein: the steel wire has a prior austenite grain size number of from 11.0 to 14.0; and a ratio (σ 0.2 /σ B ) of 0.2% proof stress (σ 0.2 ) to tensile strength (σ B ) in the steel wire is from 0.67 to 0.85.