The general definition of brazing is that it is a process that allows two metals to be joined together by a third metal, known as a filler. It is not the same as welding that uses a metal melted on the edge of each joint to create the bond, rather brazing using capillary action to draw the brazing alloy, which is softer than the two metals, into the joint and form a strong bond. Dip brazing aluminum allows parts to be brazed using a bath or a dip that provides uniform development of the braze over the entire part or piece at the same time.
The Preparation
When you prepare the part for dip brazing you are basically cleaning, positioning the parts and placing the filler material where it is going to be needed. It is essential to remove any existing oxides from all metal parts that are going to be part of the dip brazing. Hi-temp aluminum dip brazing can be used to join different types of metals or metals of different thickness all in the same process.
Once the metal is prepared the next step in dip brazing aluminum is to select the filler material and position it along the areas of the joins. The entire part or assembly is then placed in a stainless steel basket or frame that holds the part in place during the heating process as well as submersion in the bath.
The Process
The assembled part with the filler in place is then heated to a specific temperature, which is typically around 985 degrees Fahrenheit, in a specially designed furnace. This ensures that the parts are all uniformly heated but not to a level that causes the metal to melt or soften as this is not required in the dip brazing aluminum process.
From here the part or assembly is immediately placed in a bath containing flux in a solution. This is the essential component of dip brazing aluminum as this bath contains 88% aluminum and 12% silicon as well as the flux for heat transfer and uniform joints.
The liquid filler containing the dip brazing aluminum and the flux flows through the assembly, getting into even the smallest joints required much more effectively than manual or automatic brazing techniques could offer.
