Electrical resistance-pressure welding process for welding parts of workpieces made of aluminum materials and an apparatus and electrode therefor
US4591687A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 23, 1983 |
| Grant date | May 27, 1986 |
| Priority date | — |
| Expiry date | Feb 23, 2003 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12347
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Spot- and projection-welding of aluminum sheets has always been connected with difficulties mainly because of the surface layers of aluminum oxide, and even by pickling, these difficulties could be only partly eliminated. The main difficulties have always been insufficient electrode life times, the unsatisfactory quality of the weld and especially the unsolved problem of achieving good quality welding and long electrode-life when using un-pretreated aluminum sheets. The problem has been solved in principle by using electrodes having profiled contact-surfaces, by means of which the layer of oxide is broken during pre-pressing and a direct contact between the electrode and unoxidized material of the workpiece is provided, the contact-resistance of which is lower than the portion of the overall resistance of the point of weld formed by the metal of the aluminum sheets to be welded together. In an appropriate welding machine, the means for switching-on the welding current are controlled in such a manner that the welding current is switched on only after a sufficiently large contact area and therewith a sufficiently low contact-resistance of this contact has been reached.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.