Filament
US10072317B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 2015 |
| Grant date | Sep 11, 2018 |
| Priority date | — |
| Expiry date | Sep 12, 2035 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/009
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A filament according to an aspect of the present invention includes a predetermined chemical composition, in which a diameter r of the filament is 0.15 mm to 0.35 mm, a soft portion is formed along an outer circumference of the filament, the Vickers hardness of the soft portion is lower than that of a position of the filament at a depth of ¼ of the diameter r by Hv 50 or higher, the thickness of the soft portion is 1 μm to 0.1×r mm, the metallographic structure of a center portion of the filament contains 95% to 100% of pearlite by area %, the average lamellar spacing of pearlite in a portion from a surface of the filament to a depth of 1 μm is less than that of pearlite at the center of the filament, the difference between the average lamellar spacing of pearlite in the portion from the surface of the filament to the depth of 1 μm and the average lamellar spacing of pearlite at the center of the filament is 2.0 nm or less, and the tensile strength is 3200 MPa or higher.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.