Steel wire

Patent metadata

Field	Value
Publication number	US-11952650-B2
Application number	US-202017754748-A
Country	US
Kind code	B2
Filing date	Oct 15, 2020
Priority date	Oct 16, 2019
Publication date	Apr 9, 2024
Grant date	Apr 9, 2024

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/μm 2 .

First claim

The invention claimed is:

1. A steel wire having a chemical composition consisting 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,
wherein a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 per μm 2 .

2. The steel wire according to claim 1 , wherein:
in the chemical composition, a Ca content is from 0.0001 to 0.0050%; and
when, among inclusions,
inclusions in which, in mass %, an O content is 10.0% or more are defined as oxide-based inclusions,
inclusions in which, in mass %, an S content is 10.0% or more and the O content is less than 10.0% are defined as sulfide-based inclusions, and
among the sulfide-based inclusions, inclusions in which, in mass %, a Ca content is 10.0% or more, the S content is 10.0% or more, and the O content is less than 10.0% are defined as Ca sulfides,
a numerical proportion of the Ca sulfides with respect to a total number of the oxide-based inclusions and the sulfide-based inclusions is 0.20% or less.

3. The steel wire according to claim 1 , wherein,
in the chemical composition:
an Nb content is 0.005 to 0.020%.

4. The steel wire according to claim 2 , wherein,
in the chemical composition:
an Nb content is 0.005 to 0.020%.

Assignees

• Nippon Steel Corp
• Nippon Steel Sg Wire Co Ltd

Inventors

• Teramoto Shinya
• Neishi Yutaka
• AONO Michimasa
• Kozawa Shuji
• Mineta Satoru
• Ochi Tatsuro
• Suzuki Shoichi

Classifications

• C21D8/06

  during manufacturing of rods or wires · CPC title

• C22C38/54 Primary

  with boron · CPC title

• B21C1/003 Primary

  Drawing materials of special alloys so far as the composition of the alloy requires or permits special drawing methods or sequences · CPC title

• B21C37/045

  Manufacture of wire or rods with particular section or properties · CPC title

• C21D1/18

  Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62) · CPC title