Flash 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.
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.
Principle diagram of Flash welding
Some important factors for flush welding:
Work pieces must be correctly clamped with some special type of jig.
The flushing distance and upset distance must be correctly set.
Rate of application of upset pressure must be very rapid indeed.
Application of flash welding
For weld the metal sheets, rods, tubes, bars etc.
Weld the bend saw blades.
Weld the various automotive parts.
Weld the reamer, drill, tap bodies to low carbon steel shank.