In this article we will discuss about the method used for welding of aluminium and copper.
Welding of Aluminium:
Aluminium can easily be welded by gas and arc welding. Aluminium and its alloys have their melting point ranging from 550° to 700°C. At certain temperatures aluminium forms its oxides and it remains on the metal in the form of thick layer. It is very refractory material having melting point above 2750°C. Another difficulty is that the specific gravity of this oxide is higher than that of aluminium and if it is not removed then the weld will be weak throughout.
Therefore that said oxide should always be removed using a suitable flux. These fluxes are usually available in powdered form and are mixed in water to form paste before being applied. In arc welding d.c. is usually preferred for welding of aluminium. The size of electrode will be determined by the thickness of the metal.
Oxy-acetylene welding can be employed quite successfully for aluminium and to alloys welding methods, edge penetration; selection of proper welding rod and flux depends upon weather aluminium is in the form of sheets, alloy tubing, etc.
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Spot welding is very successfully done in aluminium and its alloys because of their thermal and electrical conductivity.
The process of seam welding can also be quite successfully employed for this metal and its alloys but a periodic cleaning of the rotating electrodes is necessary due to the tendency of the metal to stick to them.
Welding of Copper:
Copper is a good conductor of heat and electricity. Moreover it is a soft, ductile and tough metal. The deoxided copper is best suited for welding. It is manufactured by adding 0.15 percent silicon to prevent the formation of cuprous oxide. Similarly a suitable deoxidising material is added to the filler rod material for same purpose. Such copper can be suitably welded by most of the fusion welding processes.
The high thermal conductivity of copper usually the main difficulty in its welding. Due to this reason a great amount of heat is required to be produced at the job, so as to make good weld. D.C having straight polarity is usually employed in arc welding for welding of copper.