Welding suitability of copper materials
In the classic resistance welding world, there are often only reports about the applications in the large area of steel and now and then of aluminium (see last edition of the encyclopaedia). Outside of the familiar metal processing of these materials, the applications of copper materials are increasing rapidly. Numerous combinations of this non-ferrous metal are resistance welded, particularly in the electrical and precision engineering industries.
The experience gained from the above-mentioned materials is difficult to compare or even transfer due to the strongly differing electrical properties such as resistance and conductance. Copper materials have a very high electrical and thermal conductivity. This limits the suitability for welding suitability.
Very high welding currents are required with short welding times. Often the surfaces also have to be pretreated specifically by pickling or mechanical cleaning. In addition, special electrodes such as tungsten electrodes must be used. Due to these special requirements, almost exclusively inverter power sources in medium or high frequency design are used for these applications.
With the possibilities of these modern current sources and electrode materials, process-reliable and high-quality results are achieved and resistance welding of copper materials is being used more and more successfully. Within the framework of the DVS Working Group on Resistance Welding (V 3), Group 3.3 works specifically in the field of “Resistance Welding in Electrical Engineering and Precision Mechanics”, among other things, on precisely these topics concerning the resistance welding of copper materials.
For this purpose, too, new leaflets exist and are constantly being developed that deal with the challenges of copper materials and welding in the field of electrical engineering/fine mechanics.