Method for low-pressure carbonitriding having an extended temperature range in an initial nitridation phase
US9765422B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 8, 2012 |
| Grant date | Sep 19, 2017 |
| Priority date | — |
| Expiry date | Apr 25, 2034 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C8/80
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method for the low-pressure carbonitriding of steel parts, in particular parts used in the manufacture of automobiles comprises a heating step that includes a simple heating phase (M) followed by an initial nitridation phase (Ni) from a temperature between 700° C. to 750° C. to a temperature between 860° C. and 1000° C. and carried out using a reduced temperature gradient relative to the simple heating phase. Additionally, alternate cementing (C1-Cn) and nitridation (N1-Nn) steps are performed at constant temperature, wherein the final nitridation step is accompanied with a decrease in temperature immediately before quenching (T).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.