In collaborative research development with Audi AG, Fronius International has arrived at a new gas nozzle design that it claimed represents “a fundamental advance in the CMT brazing process.” The patented nozzle makes it possible to achieve higher brazing speeds, thereby reducing brazing costs.

The CMT, or Cold Metal Transfer process, developed by Fronius is a technology package for joining steel and aluminum, but it also addresses critical mechanical and technological objectives. It is the result of research in MIG/MAG technology that indicated – despite past difficulties and doubts - that arc welding could be a successful approach for joining the two materials.

CMT is a controlled process in which the aluminum base material melts together with the aluminum filler, with the melt wetting the galvanized steel. The filler wire is constantly retracted at very short intervals. The precisely defined retraction of the wire makes possible a precision controlled deposition of droplets, resulting in a clean, spatter-free material transfer. The wire movement takes place at a very high frequency and requires a quick-response, gearless wire drive directly on the torch. Because the main wire feeder will not be able to keep up with this movement, the wire-feeding hose provides with a wire buffer that compensates for the forward and backward movement of the wire.