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BUTT WELDING AND ITS PROCESS

There are two types of butt welding ; upset and flash :

In making of upset butt welding , the parts to be welded are clamped edge to edge in copper jaws of welding machine and brought together in a solid contact so that their point of contact forms a locality of high resistance , while current flows to heat the joint. At this point the pressure applied upsets or forges the parts together. Upset Butt Welding is used principally on non-ferrous materials for welding bars, rods, wire, tubing, formed parts, etc.

In the flash butt welding process, edges are brought together in a light contact. A high voltage starts a flashing action between the two surfaces and continues as the parts advance slowly and the forging temperature is reached. The upsetting action forces out the impurities caused by flashing. The forced-out metal is called the flash. The inner weld metal is then sound and free of oxides and cast metal. Welding rods, gas, flux, or other materials are unnecessary in this welding. Many different materials and combinations can be flash butt welded ; steels and the ferrous alloys other than cast iron are probably the most easily welded. Those materials that cannot be flash butt welded are lead, zinc, antimony, bismuth and their alloys, and the copper alloys in which these metals are present in large percentage. The flash butt welding process is used extensively in automobile construction - on the body, axles, wheels, frame and other parts. 

         Upset Butt WeldingFlash Butt Welding








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