Flash butt welding is the another kind of butt welding process. This is different from other welding process is the arcing action, the heat is being generated at a number of points by a series of tiny arcs. The works does not coming into actual contact until the final forging pressure is applied. This welding process can be carried out in another theory that very light contact does occur at number of points. Such this a very small area contact each other face. Very intense heating takes place and causes melt the metal. After current applied, vaporization takes place between the metal joining portion. The liquid metals are flowing due to capillary action. At the
same time the final mechanical forging pressure is applied, then welding current supply is cut off. This entire operation is performed automatically. The heating effect is generally produced by the electrical resistance at the joint face. Flush welding process is very quick welding process than butt welding process. Due to less time radiation losses, relatively less current is required and a smaller volume of metal is heated. The principle of flush welding diagram is shown in the bellow picture.
Some important factors for flush welding:
Application of flash welding
Principle diagram of Flash Butt welding