Upset butt welding is a welding technique that produces coalescence simultaneously over the entire area of abutting surfaces or progressively along a joint, by the heat obtained from resistance to electric current through the area where those surfaces are in contact.
The welding process used in joining mild steel shanks to high speed drills is Flash butt welding.
In arc welding, the electric arc is produced between the work and the electrode by Contact resistance.
The welding set up is said to have straight polarity, when Work is connected to the positive terminal and the electrode holder to the negative terminal.
Arc welding is a welding process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals when cool result in a binding of the metals.
For arc welding Direct current is used.