Ultra clean spring steel
US7429301B2 · kind B2 · utility
3Cited by
1References
4Claims
0Family size
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Key dates
| Filing date | Nov 23, 2005 |
| Grant date | Sep 30, 2008 |
| Priority date | — |
| Expiry date | Nov 30, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/908
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Disclosed herein is an ultra clean spring steel which contains inclusions easily elongated and broken into fine particles by hot rolling and which is easily adaptive to cold rolling and yields springs excelling in fatigue characteristics. The spring steel is characterized in that the wire contains oxide inclusions with a sulfur concentration no more than 10 mass % such that no less than 70% (in terms of numbers) of such inclusions, which exist in the outer layer outside one quarter of the diameter of the wire and have a width no smaller than 3 μm, satisfies the formula (1) below,CaO+Al2O3+SiO2+MnO+MgO>80 (mass %) . (1)
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.