1. Joint design
Joints must have adequate clearances for the filler metal to flow.
The mechanical strength of the joint varies with the clearance and overlap of base materials.
Different thermal expansion coefficients of base metals must be taken into account.
2. Cleaning (before)
The parts to be joined must be free of oil, grease, and surface oxidation.
Oil, grease, and organic residues can be removed with stripping solvents.
Hot water and detergent can also be effective.
Superficial oxides can be removed with an abrasive sandpaper.
3. Flux
The choice of flux is just as important as the choice of filler metal.
In the case of flux, the ideal is that it is applied to both parts to be joined before being assembled. And before being heated.
The flux must become active at temperatures below those of the filler metal, and remain active until the end of the operation, preventing the incidence of new oxides on the surface of the base metal.
4. Devices and fixtures for brazing
Now that the parts to be joined are clean and have flux on them, we need to keep them in the ideal position during the brazing process.
It is important that the parts are aligned during the heating and cooling cycles so that capillary action can do its part.
If the weight and geometry of the part allow it, the simplest way is to use a support or fixture.
Prefer materials that are thermal insulating.
5. Heating and applying filler metal
Different heating methods can be used.
The most common are: flame (torch), induction, resistance, and controlled atmosphere furnaces.
It is important that the base metal is heated in a linear fashion to the correct temperature.
When the brazing temperature is adequate, the flux will be transparent and will flow over the joint. Filler metal should be applied at that time.
Note that heating is done on the joint and not on the filler metal.
Alloys with high fluidity will flow through the entire space between the base metals through capillary action.
Alloys with low fluidity must be applied along the joint.
The filler metal in its liquid state always flows to the hottest part of the joint, and heating must continue while the alloy flows into the gap.
If brazing is done by a torch, indirect heating must be used and when brazing is complete, it must be discontinued.
6. Cleaning (final)
During cooling, care must be taken not to cause thermal shock to the parts, avoiding possible damage or cracks.
If the flux used is corrosive and leaves residues, it is important that they are removed through cleaning processes such as washing in warm water, mechanical action or chemical treatment.
You can increase your brazing productivity by preferring non-corrosive and non-residue fluxes.
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Citation
When you need to include a fact or piece of information in an assignment or essay you should also include where and how you found that piece of information (Brazing Procedure).
That gives credibility to your paper and it is sometimes required in higher education.
To make your life (and citation) easier just copy and paste the information below into your assignment or essay:
Luz, Gelson. Brazing Procedure and Sequence. Materials Blog. Gelsonluz.com. dd mmmm. yyyy. URL.
Now replace dd, mmmm and yyyy with the day, month, and year you browsed this page. Also replace URL for the actual url of this page. This citation format is based on MLA.
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