What we see in everyday life as lightning in a thunderstorm, welders use it in a targeted way to join metals – the electric arc. Sometimes electric arcs are also formed in the railway network, between the catenary and the pantograph. How exactly does an electric arc form and how can it be used to weld metals together?
Arc welding is a fusion welding process used to weld metals. As the name suggests, this type of welding uses an electric arc. For this to occur, there must be an electrical potential difference between two points. On the one hand, there is a negative charge, caused by an excess of electrons, and on the other, a positive electric charge, caused by a lack of electrons. It is this difference that creates the tension.
Physical forces attempt to compensate for the load imbalance by creating a voltage breakdown. A channel is then formed in which heat and high voltage ionize the gas between the poles. The result is an electrically conductive plasma. That’s where the power flows. Depending on the current source, the breakdown is manifested either as a spark or a flash. When the charge difference is balanced, it quickly goes out or continues to arc.