Moisture-free atmosphere brazing of ferrous metals
US5531372A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 1994 |
| Grant date | Jul 2, 1996 |
| Priority date | — |
| Expiry date | Aug 30, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K1/00
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The present invention discloses a novel, moisture-free atmosphere for brazing carbon steels that provides good braze flow and brazed joint quality with minimum or no formation of soot on brazed joints. According to the present invention, carbon steels are brazed in continuous furnaces using a moisture-free atmosphere containing a mixture of three gases including nitrogen, hydrogen, and carbon dioxide. The key features of the invention involve (1) formation of moisture, which is needed to facilitate braze flow and to minimize formation of soot on brazed joints, in-situ in the heating zone of the furnace by the reaction between hydrogen and carbon dioxide and (2) reduction in the overall amount of a reducing gas required for brazing carbon steels by keeping moisture out of the cooling zone. The use of a moisture-free three gas atmosphere has been unexpectedly found to (1) eliminate the need of an expensive and difficult to control external humidification system, (2) provide flexibility in adjusting moisture content of the atmosphere in the heating zone of the furnace simply by adjusting the flow rate of hydrogen or carbon dioxide or both, and (3) facilitate rapid conditioning of the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.