Fluxless Brazing of aluminum alloys using non vacuum electron beam by 60kV acceleration voltage

Abstract

Lightweight construction materials, in particular aluminum alloys, have recently become more important as construction materials due to their low weight with high strength and sufficient wear and corrosion properties. In order to be able to use the advantages resulting from the use of aluminum alloys, powerful and reliable thermal joining methods are required which reduce the heat input into the component and thus the distortion and change the set structure as less as possible. New approach here is the NV-EB brazing at low acceleration voltage. In particular, two aspects must be solved for process-reliable brazing of aluminum alloys. On the one hand, the oxide layer on the surface of the aluminum workpiece must be removed. On the other hand, sufficient heat must be put into the solder and base material in order to both melt the solder and to heat the base material sufficiently, but below the solidus temperature. Often the "Nocolok" potassium tetrafluoroaluminate flux is used. In addition, the harmful to health cesium fluoroaluminate and mixtures of both fluxes are used. Apart from health aspects, the use of fluxes has led to increased pollution of an equipment and corrosion, which contributes to process instability. By reason of described above, the investigation of a fluxless brazing of aluminum alloys using non vacuum electron beam by 60kV acceleration voltage is of great interest.