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Exothermic Welding

Exothermic Welding powder, Exothermic Weld    Accessories for Exothermic welding and Thermite weld or Thermit Weld    Thermit-Weld    Thermite Welding powder, Thermite Weld

Exothermic weld is also known as exothermic bonding, thermite welding (TW), and Thermit welding. There are many advantages of using exothermic weld. The most important one being that the process produces a molecular joint and not just a mechanical one in between the conductors. It is produced through a starting reactant which provides enough energy to activate the welding reaction. This takes place quickly and safely inside a graphite mould. The mould is designed specifically for a certain union depending on the elements to be welded and the joint type required. We guarantees all types of joints, not only copper cable unions but also to weld tapes, brass metallic pieces, stainless steel, steel ground rods covered with copper, etc. It is especially useful for joining dissimilar metals.

Features of Exothermic Weld:

  • It has Superior electrical conductivity to the conductors themselves.
  • It does not corrode, oxidize or degrade with time and is resistant to galvanic coupling.
  • It is able to withstand repeated electrical discharges.
  • It never increases its resistance.
  • It has greater mechanical and squeezing resistance than the conductors themselves.
  • It Offers a permanent welding and a low resistance connection, essential for achieving longwearing and trustworthy results in earthings.
  • It Guarantees the most common connections not only between copper cables but also for welding tapes and metallic pieces made of brass, stainless steel, and copper coated steel earth rods.

Process of Exothermic Welding

Exothermic welding, also known as exothermic bonding and thermite welding is a welding process for joining two electrical conductors, that employs superheated copper alloy to permanently join the conductors. The process employs an exothermic reaction of a copper thermite composition to heat the copper, and requires no external source of heat or current. The chemical reaction that produces the heat is an aluminothermic reaction between aluminum powder and a metal oxide.

The reaction reaches very high temperatures, depending on the metal oxide used. The reactants are usually supplied in the form of powders, with the reaction triggered using a spark from a flint lighter. The activation energy for this reaction is very high however, and initiation requires either the use of a “booster” material such as powdered magnesium metal or a very hot flame source. The aluminum oxide slag that it produces is discarded.

When welding copper conductors, the process employs a semi-permanent graphite crucible mould, in which the molten copper, produced by the reaction, flows through the mould and over and around the conductors to be welded, forming anelectrically conductive weld between them. When the copper cools, the mould is either broken off or left in place. Alternatively, hand-held graphite crucibles can be used. The advantages of these crucibles include portability, lower cost (because they can be reused), and flexibility, especially in field applications.

The weld formed has higher mechanical strength than other forms of weld, and excellent corrosion resistance. It is also highly stable when subject to repeated short-circuit pulses, and does not suffer from increased electrical resistance over the lifetime of the installation. However, the process is costly relative to other welding processes, requires a supply of replaceable moulds, suffers from a lack of repeatability, and can be impeded by wet conditions or bad weather (when performed outdoors).

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