Brazing is a thermal joining process. The required heating of the workpieces to be joined is transferred to the workpiece section by means of specially shaped inductors. The energy required for this can thus be reduced to a minimum compared to alternative brazing processes. In the following article from the magazine heat processing 3/2020, page 29, a joining process is described in which the component is exposed to a high operating temperature. The component is a steel pipe that is to be joined to a steel flange using a high-temperature brazing process. During the brazing process, shielding gas is fed directly from the inductor onto the brazing zone. This enables wetting of the base material and allows the solder to flow into the narrow soldering gap and facilitate the desired soldered joint.
The mode of operation of induction heating can be seen clearly in the video. It is important to couple the workpiece and inductor in such a way that an optimum heating pattern is produced. Overheating areas should be avoided, as should areas with too low a temperature. In both areas, correct wetting of the solder and bonding with the base material is not possible. The required uniform brazing temperature is only achieved if the inductor shape is adapted to these requirements and the supplied energy heats the brazing area optimally, i.e. power and time, possibly in several stages or controlled via pyrometer.