Heat Input and Arc Energy - why distinction is important

The welding process is a materials joining process which produces coalescence of materials by heating them to suitable temperatures with or without the application of pressure or by the application of pressure alone and with or without the use of filler material. In arc welding processes the heat necessary for coalescence is produced by an electric arc formed between the electrode and parent metal which moves along the joint. As a result, in arc welding processes the heat is localized and transient.