Abstract: Blanks or structural components of steel are joined to those of an aluminum alloy (a) or titanium alloy (b) by friction-welding with insertion of at least one transition layer of a ductile subgroup metal, in particular by applying, according to (a), a pure nickel layer to the steel by friction-welding and joining the surface of the nickel layer, after weld bead removal, to the aluminum alloy by friction-welding. According to (b), a copper layer is applied to the steel by friction-welding and a vanadium layer is applied to the titanium alloy by friction-welding. The copper and vanadium surfaces are, after weld bead removal, then joined to one another by friction-welding. In the case of steel which tends to form martensitic zones, a layer of austenitic steel is applied by friction-welding before the application of the copper layer. The process is especially suitable for joining the turbine wheel and shaft or fixing component for the shaft of a turbocharger.

Abstract: A rotary wire brush is used to transfer nickel, copper or brazing filler metal, like gold and silver from a slab of metal to the surface of a workpiece. The brush cleans the metal workpiece to expose a metal surface freshly and rubs metal of the metal slab for quick transfer for the freshly exposed metal surface of the workpiece where it sticks to build up a layer between one and one hundred microns thick in somewhere between one and two minutes. Metal slab and workpiece are both pressed against the brush, but the workpiece is not pressed enough to score the workpiece. The surface of the workpiece coated in this way can then be joined to another workpiece surface thus coated in a fluxless brazing or soldering process in which the temperature does not need to be higher than 1000.degree. C.