ERW – Electric Resistance Welding
Welded parts are put against each other and pressed with force between two metal electrodes. After this the power supply is activated; this caused the electric current variable from some units to some tens of kA in cables, electrodes and parts.
As a result the process of heating and metal’s melting starts in contact zone of parts endwise of electrodes. Tightening belt of plastically deformed metal preserves it from spitting and interaction with air. Resulted joint looks like a clincher and named as a “welded spot”.