Steel wire for high strength spring excellent in workability and high strength
US8007716B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 25, 2004 |
| Grant date | Aug 30, 2011 |
| Priority date | — |
| Expiry date | Jul 25, 2024 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C38/44
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A steel wire has tempered martensite, comprises, as essential components, by mass, C: 0.53 to 0.68%; Si: 1.2 to 2.5%; Mn: 0.2 to 1.5%; Cr: 1.4 to 2.5%; Al: 0.05% or less; further comprises, as a selective component, Ni: 0.4% or less; V: 0.4% or less; Mo: 0.05 to 0.5%; or Nb: 0.05 to 0.5%; and further comprises remainder essentially consisting of Fe and inevitable impurities, wherein the grain size number of prior austenite is 11.0 or larger, and the proof stress ratio (σ0.2/σB), namely, a ratio of 0.2% proof stress (σ0.2) to tensile strength (σB) is 0.85 or lower. Satisfying the above requirements makes it possible to produce a steel wire for high-strength spring excellent both in workability (cold workability), and in sag resistance and fatigue properties.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.