J A Gahms gata 4
S-421 31 Västra Frölunda
Tel. +46 (0)31- 748 52 25
Fax +46 (0)31- 28 64 65
Brazing is a permanent bonding technique, excellent for all kinds of metals, where welding is not useable because of it’s high working temperature and its limitation when joining different base metals. Brazing has a big advantage when it comes to joining hidden joints, when there is a risk of deformation of the base metal, temperature sensitive joints, environmental aspects. In many cases savings can be made when brazing is chosen, when after treatments might be avoided.
There are three categories of brazing; Soldering, Brazing and High temperature brazing.
Soldering is mostly used as sealing or creating permanent bonds with demands on conductivity. Soldering is being performed with a working temperature below 450°C.
Brazing includes all joints performed at a working temperature above 450°C to 1000°C. Brazing filler metals (BFM) commonly used are silverbased, silver-phosphorus, aluminum, or brass-silver (Weldbrazing) BFM. When the right joint design is made the joint becomes as strong as the base metal, and proof of Hydrogen and Helium.
High temperature brazing includes all brazing preformed over 1000°C. The high temperature brazing is done in enclosed chambers where vacuum or protection gas prevents the parts from oxidizing so that no fluxes are needed, and therefore needs no after treatment, such as pickling. A high temperature brazed joint will be stronger than the base metal and as proof as the base metal itself. The BFM are often Nickle or Cupper based.
During brazing the base metal is only heated slightly above the BFM melting temperature. This temperature is always below the melting point of the base metal. The access of alloyed BFM other properties are being obtained that the BFM main metal provides. In most brazing procedures, fluxes are being used either separately or integrated to remove oxides from the faying surfaces, to enable the BFM to wet. The flux and BMF is sucked into the joint by capillary action filling the entire joint. Depending on brazing process time, basic metal compound and the BFM’s melting range, different fluxes are available.
The most commonly used heating sources for brazed joints are: induction, torches, protection gas furnaces and vacuum furnaces. The different heating sources have different advantages depending on the quality of the joint. But the most common heating source is torch brazing.
We are suppliers to all kinds of productions, such as HVAC/cooling/heating and Automotive industry as well as maintenance and reparations. There are many different forms of BFM such as rings, flux filled rings, segments, foils, sticks, coils – to mention a few. No tasks are too difficult for us and we offer custom made solutions, investigations, casualty reports, quality improvements and custom-made educations.