Ferritic and martensitic stainless steels excellent in machinability
US7070663B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 2003 |
| Grant date | Jul 4, 2006 |
| Priority date | — |
| Expiry date | Feb 22, 2024 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A ferritic or martensitic stainless steel has the structure that Cu-enriched particles with concentration of C not less than 0.1 mass % or concentration of Sn and/or In not less than 10 mass % were dispersed in a matrix. Precipitation and dispersion of Cu-enriched particles is realized by aging the stainless steel at 500–900° C. for 1 hour or longer on any stage after a hot-rolling step until a forming step to a final product. The ferritic stainless steel contains 0.01–1.0% C, Si up to 1.0%, Mn up to 1.0%, 15–30% Cr, Ni up to 6.0% and 0.5–6.0% Cu. The martensitic stainless steel contains 0.01–0.5% C, Si up to 1.0%, Mn up to 1.0%, 10–15% Cr, Ni up to 6.0% and 0.5–6.0% Cu. Since Cu-enriched particles are dispersed for improvement of machinability instead of addition of S, Pb, Bi or Se, the stainless steel is machined to an objective shape without any harmful influence on workability, corrosion-resistance and the environment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.