A simple test method for the welding degradation of arcing contacts

Abstract:
In some switching situations arcing contacts are subject to welding degradation, which limits the performance and lifetime of the device. Usually such a behaviour is studied in long-term tests applying numerous switching operations. However, for contact material selection at an early development stage, a fast screening method would greatly benefit the material selection process. In the present work, a simple method based on stud-welding and tensile testing was deployed. Cu-Cr materials with different Cr concentrations were tested and subsequently analysed by light-optical microscopy. The test method as well as the microstructural material degradation are discussed in detail. Based on the results of the welding tests, a ranking of the welding performance of the investigated Cu-Cr materials is given.