An electrode is a wire carrying a strong current forming an arc with the work piece. Usually the wire as well as part of the work piece melt together, the wire alloying the work piece. Some electrodes, (graphite or tungsten alloys) are used to establish the arc, without melting themselves.

a) Electrodes which melt

o Coated electrodes
o Bare electrodes (MIG - MAG welding)
o Flux cored wires

b) Electrodes which do not melt

These electrodes form the arc in which and an additional filling wire melts.

There are three types of welding electrodes:

a) Electrodes used in assembly welding
b) Electrodes used in hard surfacing
c ) Electrodes used in chamfering and cutting

Electrodes used in assembly welding should have:

a) A sufficient tensile strength
b) High yield point and impact strength

Electrodes used in hard surfacing should have:

a) A required hardness
b) Resistance to wear