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| BRAZING |
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| Brazing is a welding process, which produces coalescence
of materials by heating them to a suitable temperature
and by using a filler metal having melting point
above 450°C. The filler metal is distributed between
closely fitted surfaces of the joint by capillary action. |
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| The placement of the filler metal affects the quality of the joint. For normal lap joints, the filler metal should be
supplied from one end only and allowed to flow completely through the joint by capillary action. |
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| The correct fluxing material must be used. The placement
of the flux also affects the quality of the brazed
joint. Paste flux is the most common from and is usually
spread over the surfaces to be joined. It is also painted
on the pre-placed brazing filler materials. |
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| For some of the brazing methods a special atmosphere
is used instead of flux, which is selected based on the
metals being joined. When atmospheres are used flux
may not be required. The atmosphere is the product of
the combustion of the flame. The neutral or reducing
flame is usually used. A slightly oxidising flame may be
used for certain other materials. The general guideline
for selection of flames is given below |
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| Aluminiums |
Slightly reducing |
| Brasses |
Slightly oxidising |
| Bronzes |
Slightly oxidising |
| Copper |
Neutral |
| Cupro-nickel |
Reducing |
| Inconel |
Slightly reducing |
| Cast Iron |
Neutral |
| Wrought Iron |
Neutral |
| Monel |
Slightly reducing |
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| More Info... |
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