Welding The exothermic welding process
The exothermic welding process is a simple and safe method which does not require an external source of large heat or electric power for making copper to copper, copper to steel or steel to steel connections for the conduction of electricity.
A semi permanent graphite mould is used for making connections by exothermic process. The mould is placed over the conductors to be joined. The weld powder is poured into the mould cavity after placing the thin metal disc to block the downward passage of the powder .The top lid is closed and a spark is produced by a flint gun to ignite the powder inside the mould.
The ignition of weld powder causes high temperature exothermic reactions and the formation of aluminum oxide slag and molten copper. The molten copper melts the thin disc blocking its downward passage and flows through onto the conductors to be joined. A fusion weld is formed between the conductors in this process
The majority of exothermic welding connections have at least twice the cross sectional area of the welded conductors and equivalent or greater current carrying capacity. Since the connection is fusion of virtually pure copper it can withstand high current surges and does not loose or corrode at the point of weld.
The selection guide shows the typical materials necessary for cathodic protection connections. Further information and advice on mould, clamp and powder size for any particular application, can be provided on request
- Lid
- Starting power
- Graphite mould
- Weld metal powder
- Steel disc
- Tap hole
- Weld cavity
- Conductor
- Earth rod