SPRING STEEL HAVING SUPERIOR FATIGUE LIFE, AND MANUFACTURING METHOD FOR SAME

Title:

SPRING STEEL HAVING SUPERIOR FATIGUE LIFE, AND MANUFACTURING METHOD FOR SAME

Document Type and Number:

WIPO Patent Application WO/2020/020066

Kind Code:

A1

Abstract:

A spring steel having a superior fatigue life, and a manufacturing method for the same. The chemical components thereof are as follows in weight percentage: C: 0.52-0.62%, Si: 1.20-1.45%, Mn: 0.25-0.75%, Cr: 0.30-0.80%, V: 0.01-0.15%, Nb: 0.001-0.05%, N: 0.001-0.009%, O: 0.0005-0.0040%, P: ≤ 0.015%, S: ≤ 0.015%, and Al: ≤ 0.0045%, with the remainder being Fe and incidental impurities, wherein the following condition is also met 0.02 ≤ (2Nb+V)/(20N+C) ≤ 0.40. The spring steel of the present invention has a microstructure of tempered troostite + tempered sorbite, a prior austenite grain size less than 80 um, a size of alloy nitride and carbide precipitates being 5-60 nm, and a maximum width of single-grain inclusions being less than 30 um. The spring steel has a handling strength greater than 2020 MPa, superior ductility and toughness (the reduction of area ≥ 40％), and a fatigue life ≥ 800,000 times, thereby meeting application requirements of high-stress springs in industries, such as automobiles, machinery, and the like.

Inventors:

YAO ZAN (CN)
JIN FENG (CN)
WAN GENJIE (CN)
QI YANFENG (CN)
WU ZHENPING (CN)

Application Number:

PCT/CN2019/096726

Publication Date:

January 30, 2020

Filing Date:

July 19, 2019

Export Citation:

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Assignee:

BAOSHAN IRON & STEEL (CN)

International Classes:

C22C38/00; C21D7/06; C21D9/02; C22C38/24

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CN101787493A	2010-07-28
CN100455691C	2009-01-28
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Other References: