Gas-shielded brazing of pipe sections
If a normal ring inductor cannot be used for brazing pipe sections, it is possible and practical to use folding inductors. In the example shown, four alternately operated folding inductors with shielding-gas device ensure that around 1.2 million workpieces can be brazed automatically each year. A high-melting-point copper alloy is used as the filler metal. While one part is being brazed, the previously brazed part is cooling down under shielding gas, another brazed and cooled part is being removed from the holder, and a new part to be brazed is being loaded at the fourth holder. The pure brazing time per part is around 12 sec.
Pipe sections can be brazed both with flux and silver filler metal and with high-melting-point copper filler metals and shielding gas. Depending on quantities, HF or MF generators with one or more outputs are used. In this example, a 10-kW HF generator of the type eldec HFG 10-4 with four switchable outputs was used.