Joining of steel-aluminium mixed joints with energy-reduced GMA processes and filler materials on an aluminium and zinc basis

摘要

Steel and aluminium exhibit great differences in their chemical and physical properties. During thermal joining, diffusion processes in the interfacial area result in intermetallic layers consisting of brittle, intermetallic phases which exert a negative influence on the joint properties. The heat input and thus the phase growth can be reduced considerably by using energy-reduced gas metal-arc welding processes. In addition, new developments of the controlled short arc technology permit a substantial decrease in the power peaks in the welding process. In the case of zinc-based brazing materials which have been unsuitable for GMA processes until now because of their low vaporisation temperatures, it was possible to reduce the eruptive vaporisation in this way. In this article, the suitability of various brazing materials for the manufacture of mixed joints is investigated using the example of the CMT (cold metal transfer) process. The properties of the joints are compared with each other on different sheet thickness combinations.