“Exothermic weld” is a simple, cost-effective and permanent welded connection that uses a high-temperature exothermic reaction to create a molecular bond. It does not require an external heat or power source. Exothermic weld is the universally preferred method for making permanent copper-to-copper and copper-to-steel electrical connections. Its performance is superior to all existing surface-to-surface mechanical connectors. “Exothermic weld works when others won’t!”
Live Exothermic Welding Process/Procedure
Exothermic Weld System is a very effective and cost efficient method of making electrical connections in high quality which includes Large Connection or Small Connection. It is a simple self-contained system that uses the high temperature reaction of powdered copper oxide, aluminium and other required chemical and materials, within a mould to form permanent electrical connections.
What and Which Metal can be Weld through Exothermic Weld Powder ?
The process of exothermic Weld is a method of making electrical connections from Copper to Copper or Copper to Steel and it can join any Metals to Metals like Bronze, Galvanized metals and Stainless steel etc , in which no outside source of heat or power is required.
In Exothermic Weld Process, the following are the steps
Step 1 – The two conductors that is to be joined are placed in the Weld cavity and than the steel disc is located in the base of the crucible in the Graphite Mould.
Step 2 – After the disc is placed in the Mould, Exothermic Weld Powder Material is poured down into Graphite Mould followed by Starting Powder
Step 3 – Some Ignite Powder should also be sparkled on the Mouth of Mould and than ignited by Flint Gun.
The process of igniting the particles creates extremely high heat i.e upto 1400 degree Celcius and produces Exothermic Reactionwhich also melts the Steel Disc and then the Exothermic Weld Powder flows into the Weld cavity thus filling any available space and completes the Weld. In Weld cavity the molten copper alloy partially melts the conductors. The molten copper alloy gets cooled and forms a fusion Weld which solidify before it is removed from the mould.
This entire process takes only upto 10 to 15 seconds to complete. Then the mould is ready for the next Weld after a brief cleaning with a brush. Exothermic Welded connections produce a permanent connection, superior in performance to any known mechanical or pressure type surface-to-surface contact connector. Due to the fact that the connection produced is a molecular bond so an exothermic Welded connection will not loosen and there will be increase in resistance over the lifetime of the installation.
The Process is very Simple and hence a Laymen can do the Job Work by just seeing the process once. Hence one need to ensure that the process should be undertaken carefully and proper instruction should be maintained by the Laymen.
exothermic weld is a process that achieves the molecular binding among two or more metallic conductors by a chemical reaction. This molecular binding improves mechanical, electrical and anti-corrosion properties compared with any mechanical connection.exothermic weld is the best way to make permanent, reliable and high conductivity connections for any installation requiring an earthing system.
Type of Joints possible from Exothermic Weld:
1) Horizontal Joints
2) Vertical Joints
3) Straight Joints
4) Cross Joints
5) Overlap Joints
6) L shape Joints
7) T shape Joints
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.
The Exothermic Weld Connecting created a permanent, homogeneous, and molecular bond that cannot loosen or corrode, and will carry more current that the conductor.
The Exothermic Weld Connection are solid molecular bonds, they do not loosen or corrode over the lifetime of connection. The ame cannot be said about other methods; such as brazing, crimp, split bolt, or compreion type connections.
Advantages and Disadvantages of Exothermic Weld:
Compared for some other forms of welding, exothermic bonds employ a greater mechanical toughness. The weld can be proof against corrosion. You simply won’t notice an increase in electrical excess weight despite repeated small signal pulses; your weld is highly firm. The procedure is more costly, however. The task requires replaceable moulds, is not easily repeatable.
Exothermic weld may also be done far from others. That reduces dangers to employees. A igniter is used with widespread graphite molds or a palatable made drop within weld metal ink cartridge, semi-permanent graphite crucible pattern, and an ignition company that connects your container with a cord.
Exothermic weld is usually used for welding copper conductors but is suitable for welding a wide range of metals, including stainless steel, cast iron, common steel, brass, bronze, and Monel. It is especially useful for joining dissimilar metals.
Because of the good electrical conductivity and high stability in the face of short-circuit pulses, exothermic welds are one of the options specified by the grounding conductors and bonding jumpers. It is the preferred method of bonding, and indeed it is the only acceptable means of bonding copper to galvanized cable. The NEC does not require such exothermically welded connections to be listed or labelled, but some engineering specifications require that completed exothermic welds be examined using X-ray equipment.
An exothermic weld 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 otherwelding processes, requires a supply of replaceable moulds, suffers from a lack of repeatability, and can be impeded by wet conditions or bad weather.
Exothermic welding is a simple self contained method of making high quality electrical connections for welding copper to copper, copper alloy such as brass, bronze or copper to steel.
- The exothermic welding system uses the high temperature of reaction of powdered copper oxide and aluminium.
- The reaction takes place in a graphite mould, which is machined according to the conductor sizes to be welded and which can be used for approx.
- 60 welds or more welds if properly cared for.
- The reaction last a few seconds only and the process requires no external power or heat source, making it completely portable and ideal for field use.
- Typical applications include earthing of sub-stations and power plant, cathodic protection, rail connections, lightning protection, telecommunications, etc…
- An exothermic welding shows a lot of advantages in comparison to mechanical or crimping systems.
As it is a molecular weld it will not be affected by high current surge. It can be
shown by tests that the electrical conductor will melt before the exothermic weld when subject to high short circuit current.
The weld metal has the same melting point as copper and the cross section of the weld is higher than the cross section of the conductors to be welded so that the current carrying capacity is greater than that of the conductors.
In addition to copper material such as brass, bronze, stainless steel, steel rail, etc… may also be welded.
The result will be a connection composed of an alloy without dielectric influence at the exothermic weld point and totally unaffected by corrosion.
Exothermic Welding – Properties
An exothermic weld 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).
Exothermic Welding – Applications
Exothermic Welding is usually used for welding copper conductors but is suitable for welding a wide range of metals, including stainless steel, cast iron, common steel, brass, bronze, and Monel. It is especially useful for joining dissimilar metals. The process is marketed under a variety of names such as APLIWELD (in tablet form), American Rail Weld, Harger ULTRASHOT, ERICO CADWELD, Quikweld, Tectoweld, Ultraweld, Techweld, TerraWeld, Thermoweld, Ardo Weld, AmiableWeld, AIWeld, FurseWeld and Kumwell.
It is the preferred method of bonding, and indeed it is the only acceptable means of bonding copper to galvanized cable.