Invention Grant
- Patent Title: High-strength spring steel wire
- Patent Title (中): 高强度弹簧钢丝
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Application No.: US10362651Application Date: 2001-12-20
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Publication No.: US07789974B2Publication Date: 2010-09-07
- Inventor: Masayuki Hashimura , Hiroshi Hagiwara , Takanari Miyaki
- Applicant: Masayuki Hashimura , Hiroshi Hagiwara , Takanari Miyaki
- Applicant Address: JP Tokyo
- Assignee: Nippon Steel Corporation
- Current Assignee: Nippon Steel Corporation
- Current Assignee Address: JP Tokyo
- Agency: Kenyon & Kenyon LLP
- Priority: JP2000-386900 20001220; JP2000-386901 20001220; JP2000-386902 20001220; JP2001-1364875 20011129
- International Application: PCT/JP01/11216 WO 20011220
- International Announcement: WO02/50327 WO 20020627
- Main IPC: C22C38/18
- IPC: C22C38/18 ; C22C38/34

Abstract:
The present invention provides a spring steel having both a high strength and a good coiling property after heat treatment, characterized by: containing, in mass, C: 0.4 to 1.2%, Si: 0.9 to 3.0%, Mn: 0.1 to 2.0%, P: 0.015% or less, S: 0.015% or less, Cr: 2.5% or less, and N: 0.001 to 0.015%, with the balance consisting of Fe and unavoidable impurities; and, in the microstructure of the steel after hot rolling, the density of globular cementite carbides 0.2 to 3 μm in circle-equivalent diameter being 0.5 piece/μm2 or less and the density of globular cementite carbides over 3 μm in circle-equivalent diameter being 0.005 piece/μm2 or less.
Public/Granted literature
- US20030201036A1 High-strength spring steel and spring steel wire Public/Granted day:2003-10-30
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