Electric Resistance Welding
It is a type of pressure welding. It is used for joining picess of sheet metal or wire . The welding heat is obtained at the location of the directed weld by the electrical resistance through the metal picess to a relatively short duration , low voltage ( From 6 to 10 V only). High ampere ( varying from 60 to 4000 Amp). The amount of current can be regulated by changing the primary turns of transformer . When the area to be welded edges sufficiently heated , the pressure varying from 25 to 50 MBa is applied to joining area by suitable electrodes until the welding is solid .
What is welding ?
The welding is a process of joining two similar metals by fusion with or without the applicayion or pressour and with or without the used of filler metal.
The commnly used joints in fusion welded are lap joimt ,but joimt ,edge joint and T-joint .
The lap joint are employed on plates habing thickness less then 3m.m . In but welds the plates edges doesn't requare beving if the thickness of plate is lass then 5 m.m . In the plate thickness 5 m.m to 12 m.m the edge should be bevelled to V or U groove and plates having thickness above 12.5 m.m should have a V or U groove on both side.