Damper spring

Patent metadata

Field	Value
Publication number	US-12181012-B2
Application number	US-202017754566-A
Country	US
Kind code	B2
Filing date	Oct 15, 2020
Priority date	Oct 16, 2019
Publication date	Dec 31, 2024
Grant date	Dec 31, 2024

Abstract

A damper spring having an excellent fatigue limit is provided. A damper spring according to the present embodiment includes a nitrided layer formed in an outer layer, and a core portion that is further inward than the nitrided layer. The chemical composition of the core portion 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, and Nb: 0 to 0.020%, with the balance being Fe and impurities. In the core portion, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 pieces/μm2.

First claim

The invention claimed is:

1. A damper spring, comprising:
a nitrided layer formed in an outer layer, and
a core portion that is further inward than the nitrided layer;
wherein:
a chemical composition of the core portion 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, and
Nb: 0 to 0.020%,
with the balance being Fe and impurities; and
in the core portion, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 pieces/μm 2 .

2. The damper spring according to claim 1 , wherein:
in the chemical composition of the core portion:
an Nb content is 0.005 to 0.020%.

Assignees

• Nippon Steel Corp
• Aisin Corp
• Nhk Spring Co Ltd
• Nippon Steel Sg Wire Co Ltd

Inventors

• Teramoto Shinya
• Neishi Yutaka
• AONO Michimasa
• Kozawa Shuji
• Oi Yoichi
• Takabayashi Naoki
• Tanaka Junji
• Takahashi Fumio
• Nishimoto Shigekazu
• Kondo Mitsuhiro
• Ochi Tatsuro
• Suzuki Shoichi

Classifications

• C21D8/06

  during manufacturing of rods or wires · CPC title

• F16F2224/0208

  Alloys · CPC title

• F16F1/04

  Wound springs {(making springs by coiling wire B21F3/00)} · CPC title

• C23C8/26

  of ferrous surfaces · CPC title

• C22C38/50

  with titanium or zirconium · CPC title