welding

welding

1. process [automated]

   • the materials to be joined are over lapped.
   • two electrodes press in on the materials from either side
   • a large current is passed between the electrodes
   • the materials melt and fuse in one "spot" or "nugget"
   • the electrodes open, and move on to, or get ready for the next spot weld
   • portable spot welders are also available

2. resistance welding

   • resistance welding passes a large electric current through the material to melt and fuse the parts. no shielding flux or gas is needed because the join is internal and not exposed to the air.

3. heat source

   • electric current flowing against the electrical resistance