The correct choice of flux is the key to good brazing practice and many problems arise from the incorrect selection or ineffective application of flux. A good match between the flux and the brazing alloy/parent metal combination is essential if strong, sound joints are to be produced.
The flux layer performs the critical function of cleaning and protecting the surface of the parent metal during brazing, and so facilitates the ‘wetting’ and flow of the brazing alloy.
Not only is it important that the proper flux is selected, but also that sufficient flux is applied to the joint area to provide protection throughout the brazing cycle. A further benefit is, that if excess fluxis applied in the immediate joint area, oxidation of adjacent surfaces may be prevented, so reducing post-brazing cleaning costs.
As a guide, the flux selected should be active at least 50°C below the solidus and 50°C above the liquidus of the brazing alloy selected.
Our range of fluxes is available as either powder or paste in a range of packaging. Please consult your Sales Office for technical support.
Specialist fluxes are available for specific customer requirements.