The brazing is the assembly of two materials using a filler having a Melting point lower than that of metals to assemble and wetting, by capillarity, surfaces which do not take part by their fusion in the constitution of the brazed and soldered joint. It is an assembly known as “heterogeneous”.

The heating of the zone to be brazed can be made by a Soldering iron, hot air, a flame (Chalumeau), a Electric arc, a Inducteur or with the Laser.
Brazing can also be done with the furnace (with air, under controlled atmosphere, vacuum).

This process for example is used:

  • in electronic to assemble the components on the printed circuits, or various elements between them, while ensuring electric continuity.
  • in Plumbing to assemble tubes in a tight way (brazing by capillarity).
  • in auto industry (exchangers of standard heat condenser and evaporator).
  • in aircraft industry and aerospace (vacuum brazing of stainless and superalloys).
  • in the manufacture of the musical instruments.
  • in the manufacture of Jewels and jewels.

The filler can be an alloy of tin, Cuivre, money, Aluminum, Nickel, or other metal alloys précieux.
Very frequently of the Flux of brazing are used in order to allow the damping of the filler by destruction of the oxide coating the surface of metals to be assembled.

Brazing and weak

Brazing is a mode of brazing in which the melting point of filler metal is higher than 450°C.

Contrary, for a melting point of filler metal lower than 450°C, one will speak about soldering.

Brazing of electronics components

In electronics, the filler generally consisted of 60% of tin and 40% of Plomb in mass in order to produce an eutectic mixture almost (point melting lower than 190 °C).

The eutectic report/ratio of 63/37 (%m) corresponds of close in Sn3Pb mixes Intermétallique. It gives an eutectic around 179°C to 183°C.

The current trend is to reduce the quantity of lead and to find other alloys, because of toxicity.

Evolution

According to the directives of the European Union WEEE ( Waste off Electrical and Electronic Equipment ) and RoHS ( Reduction off Hazardous Substances ), the Plomb must be eliminated from the electronic systems starting from July 1st 2006, bringing a great interest of the industrialists for brazings without lead. Those contain tin, copper, money, and other metals in varied quantities.

See the article assembled Composant surfaces of it for more details on the implications of these changes in the electronics industry.

Brazing used in plumbing

In Plumbing, a higher proportion of lead was used. What had the advantage of making more slowly take the brazing, and which thus made it possible to slip it on the joint to ensure the sealing. With the replacement of the lead drains by copper, lead in brazings was replaced by copper, and the proportion of tin increased.

The filler used for brazing is generally an alloy coppers Phosphore of copper zinc, or coppers/argent.
The melting point of these different alloy is generally between 600°C and 880°C.
The alloys with strong content silver (40%) are recommended for the realization of brazings to high mechanical resistance and are only authorized for connections of gas pipelines of city out of copper and laiton.
The Laiton is used for the brazing of the Acier.

Brazing in general is mixed with, or is used with flow, which is a reducing agent designed to help to remove the impurities (in particular metals oxidized S. For the aspect practices the filler is often marketed in the form of rods or like hollow tubes containers of flow. The majority of cold brazings are sufficiently flexible to be rolled and stored in roller.

Brazing in the musical instruments

In invoice of organ, this process is used in order to manufacture the pipes. The technique to be acquired is not obvious and requires a specific CAPE. The pipes are made of an alloy either rich in tin (>63.3%), or poor (<63.3%). The ideal being that this alloy is not too close to alloy used to braze. The bars of welding are to 63.3% of tin because it is with this percentage that the melting point is with lowest.

External bonds

  • Soudeur.com: The French-speaking site gate of the welder, the welding and welding

Brazing Soldering

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