Steel wire

US11952650B2 · kind B2 · utility

Assignees

• NIPPON STEEL CORPORATION · JP
• NIPPON STEEL SG WIRE CO., LTD. · JP

Inventors

• Shinya Teramoto · Tokyo, JP
• Yutaka Neishi · Tokyo, JP
• Michimasa Aono · Tokyo, JP
• Shuji Kozawa · Anjo, JP
• Satoru Mineta · Tokyo, JP
• Tatsuro Ochi · Muroran, JP
• Shoichi Suzuki · Tokyo, JP

Key dates

• Filing date: Oct 15, 2020
• Grant date: Apr 9, 2024
• Expiry date: Oct 15, 2040

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16F2224/0208
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A steel wire which has an excellent fatigue limit when made into a spring is provided. A chemical composition of the steel wire according to the present embodiment consists of, in mass %, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, S: 0.020% or less, Cr 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, N: 0.0070% or less, Ca: 0 to 0.0050%, and Nb: 0 to 0.020%, with the balance being Fe and impurities. In the steel wire, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 pieces/μm2.