Steel wire rod for hard drawn spring, drawn wire rod for hard drawn spring and hard drawn spring, and method for producing hard drawn spring
US7074282B2 · kind B2 · utility
7Cited by
15References
16Claims
0Family size
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Key dates
| Filing date | Dec 19, 2001 |
| Grant date | Jul 11, 2006 |
| Priority date | — |
| Expiry date | Dec 22, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/009
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Disclosed is a steel wire rod for hard-drawn springs capable of exhibiting fatigue strength and sag resistance equivalent to or higher than springs made of an oil-tempered wire. The steel wire rod contains carbon in a range from 0.5 to less than 0.7 mass %, silicon in a range from 1.4 to 2.5 mass %, manganese in a range from 0.5 to 1.5 mass %, chromium in a range from 0.05 to 2.0 mass %, and vanadium in a range from 0.05 to 0.40 mass %, and has an area ratio Rp with respect to pearlite which satisfies the mathematical expression (1):Rp(area %)≧55×[C]+61 (1)where [C] denotes the content (mass %) of carbon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.