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.