Resistance welding is a method of welding using an intrinsic property – electric conductivity. Two or more workpieces are welded based on the effect of heat emission on the contact point of welded metal elements (characterised by greater resistance) during a current flow (Joule-Lenz law) and pressure force of current supplying electrodes. The welded elements heat and melt, and then blend naturally.
Resistance welding procedure:
- pressing the workpieces to be welded against one another with the welder electrodes
- heating of elements in the welding spot and formation of a liquid nucleus of the weld
- cooling of the weld nucleus and formation of a uniform connection
- welding current intensity
- current flow time
- dimensions of the electrode-material contact point
- electrode pressure force
Engineering equipment – metal welders – is used for resistance welding. Depending on the design, the equipment can be supplied with alternating current (with the mains frequency of e.g. 50 Hz) or direct current obtained by rectification of alternating current with the mains frequency (e.g. 1000 Hz) – inverter welders.
Standard welders are classified as follows: