Welding according to DIN 1910
“Welding is the joining of materials in the weld zone using heat and/or force with or without a filler metal”.
The heat required for welding is generated by current flow via the electrical resistance of the welding zone.
Heat is generated at the welding point by the interaction of welding current, resistance and welding time according to Joule’s law:
Q = I2 x R x t