For hard drawn steel wire spring with an excellent fatigue strength and a decrease in resistance and hard drawn spring

摘要

A steel wire for a spring which has a chemical composition: C: 0.5 to 0.7 %, Si: 1.0 to 1.95 %, Mn: 0.5 to 1.5 %, Cr: 0.5 to 1.5 % and balance: Fe and inevitable impurities, and contains carbide precipitates having a diameter of a corresponding circle of 0.1 μm or greater in an amount of 5 pieces/100 μm2 or less. A hard drawn spring using the above steel wire exhibits the fatigue strength and the resistance to settling comparable or superior to those of a spring using an oil-tempered steel wire.