Heat treating atmospheres from non-cryogenically generated nitrogen
US5302213A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1992 |
| Grant date | Apr 12, 1994 |
| Priority date | — |
| Expiry date | Dec 22, 2012 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K35/383
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An improved process for producing nitrogen-based atmospheres suitable for annealing ferrous metals and alloys, brazing metals, sintering metal and ceramic powders, and sealing glass to metals from non-cryogenically generated nitrogen is presented. These atmospheres are produced by 1) humidifying non-cryogenically generated nitrogen containing less than 5.0 vol. % residual oxygen, 2) mixing it with a specified amount of a hydrocarbon gas, 3) feeding the gaseous mixture into the heating zone of a furnace through a diffuser, and 4) converting in-situ the residual oxygen and moisture present in it to a mixture of carbon dioxide, carbon monoxide, moisture, and/or hydrogen. The key features of the present invention include a) humidifying the feed gas prior to introducing it into the heating zone of a furnace operated above about 800.degree. C. and b) using enough amount of a hydrocarbon gas to facilitate in-situ conversion of residual oxygen and moisture present in the feed gas to a mixture of carbon dioxide, carbon monoxide, moisture, and hydrogen in the heating zone of a furnace.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.