High-strength spring steel wire with excellent hydrogen embrittlement resistance, manufacturing process therefor, and high-strength spring

Patent metadata

Field	Value
Publication number	US-9970072-B2
Application number	US-201314439864-A
Country	US
Kind code	B2
Filing date	Dec 2, 2013
Priority date	Dec 21, 2012
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A high-strength spring steel wire is provided which secures excellent hydrogen embrittlement resistance even when the adding amount of alloy elements is suppressed, and has 80 area % or more of tempered martensite and 1,900 MPa or more of the tensile strength, in which a predetermined chemical composition is satisfied, with C and Si satisfying the relation of the expression (1) below, with prior austenite grain size number being No. 10 or more, and with the hydrogen absorption amount being 14.0 ppm or more.

0.73%≤[C]+[Si]/8≤0.90%  (1)

where [C] and [Si] express the content (mass %) of C and Si respectively.

First claim

The invention claimed is:

1. A high-strength spring steel wire with 80 area % or more of tempered martensite and 1,900 MPa or more of tensile strength, wherein:
the wire consists of:
C: 0.50-0.70% by mass;
Si: 1.50-2.3% by mass;
Mn: 0.3-1.5% by mass;
P: 0.015% or less by mass, exclusive of 0%;
S: 0.015% or less by mass, exclusive of 0%;
Al: 0.001-0.10% by mass;
Fe; and
optionally one or more elements selected from the group consisting of (a) to (f):
(a) at least…

Assignees

• Kobe Steel Ltd

Inventors

• Takeda Atsuhiko
• Yoshihara Nao

Classifications

• C21D8/06

  Chemistry & Metallurgy · mapped topic

• C22C38/12

  Chemistry & Metallurgy · mapped topic

• C22C38/06

  Chemistry & Metallurgy · mapped topic

• C22C38/34

  Chemistry & Metallurgy · mapped topic

• C21D6/004

  Chemistry & Metallurgy · mapped topic