Induction Brazing

Induction brazing is a type of brazing process in which the joints are produced by the heat obtained from the resistance of the work to the flow of induced electric current. A nonferrous filler metal is used , which has the melting temperature above 427 °C (800 °F) but below the base metals.


Usage of Induction Brazing
Induction brazing is particularly used where :

• There is a requirement of high production rate
• Very fast heating is needed.
• Assembly parts are self jigging

The Process
Induction brazing follows a particular process where the components to be brazed are fluxed, filler metal is preplaced as in a ring or a washer form in proper position. This assembly is placed within an induction coil through which when high frequency electric current passes, the energy gets transmitted to the assembly/workpiece by induction. The workpiece surface starts getting heated because of the eddy currents in the work metal which due to its electrical resistively and the flow of induced alternating current through it generates heat.

The workpiece's interior is actually heated by thermal conduction from the hot surface. Heating intensity of the workpiece depends upon the frequency of the alternating current employed. Meaning thereby, the heating intensity & frequency is indirectly proportionate to each other.

The induction brazing involves usages of induction coils, since, they induce localized heat in the materials needed to be brazed. Because of the resistance towards the flow of current induced in conducive materials when aptly placed in a magnetic field produced by quick alternating current that the heating process occurs. Induction coils generate the alternating current in the parts which are to be to be brazed.

Materials
Though, silver based brazing alloys are extensively used for Induction brazing, copper is as well used. Suitable for many metallic materials, Induction brazing is perfect for magnetic materials which are readily heated. Heating occurs by conduction from surrounding metallic parts or with the use of a susceptor in case of the involvement of ceramic material.

Advantages
Induction brazing have their own set of benefits when compared to other brazing methods. Let us take a look at these salient features.

• This kind of brazing is comparatively better because it is selective and produces rapid heating.
  
  
• Has a precise heat control and is suitable for large volume production.
  
  
• It associates high-speed localized heating that minimizes oxidation. Therefore, no requirement for further cleaning.
  
  
• Warpage is less when the entire assembly is heated, since, heating is localized. All leads to minimal metallurgical changes, such as the softening of cold worked or heat treated metal.
  
  
• Even a less skilled operator can execute a process since power output and time at heat can both be precisely controlled in induction heating.
  
  
• It provides localized heating, precise control of both heating rate and final temperature.
  
  
• The method can be mechanized and, therefore, multi-brazing stations for one power source.

Precautions
Lot of precaution is required while conducting induction brazing & it generally includes the ones which are frequently applied for mechanical and electrical equipment as well for handling of hot components. Care is required when dealing with high frequency electromagnetic field which further ensures that it does not gets released to the general work environment.