Corrosion resistant steel components and method of manufacture thereof
US4596611A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 5, 1984 |
| Grant date | Jun 24, 1986 |
| Priority date | — |
| Expiry date | Nov 5, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C8/80
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A non-alloy steel component is nitrocarburized at 550.degree. to 720.degree. C. for up to 4 hours in a nitriding gaseous atmosphere e.g. ammonia or ammonia and endothermic or exothermic gas, and is thus exposed to air or other oxidizing atmosphere for 2 to 120 seconds to form an oxide-rich layer thereon before being quenched into an oil/water emulsion, degreased and a tack-free wax coating applied. Alternatively, the component may be cooled in air or other oxidizing atmosphere and then wax coated or it may be cooled in a non-oxidizing atmosphere and then reheated to provide the oxide-rich surface layer before being cooled again and wax coated. As a further alternative, the component may be cooled, lapped to a surface roughness of not more than 0.2 micrometers Ra, reheated to oxidize and then quenched. These techniques give a good corrosion resistance to the component.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.