Question

Five common welding methods are: oxy-acetylene gas welding; tungsten-inert-gas (“TIG”) welding; metal-inert-gas (“MIG”) welding; resistance spot welding; and laser welding. Of these five methods, which are applicable to carbon steels and which to wrought aluminum alloys? Discuss.

Answer 1

For Aluminum -

Aluminum has certain properties which make it difficult to weld, such as its high thermal conductivity and low melting point & the other difficulty is formation of oxide layer which has melting point around three times the melting point of aluminum. Only fusion welding can be used to weld aluminum alloys. MIG and TIG are mostly used for aluminum alloys. TIG was mainly developed to weld Aluminum alloys. Oxyacetylene welding can also be used to weld aluminum it is less expensive than TIG & MIG. Spot welding can also be used to weld aluminum but the current requirement will be high. Laser beams are used for aluminum welding as HAZ formation is less.

So for Aluminum all the welding process can be used but mainly TIG and Laser are used.

For Carbon steels Oxyacetylene, spot welding are used. Low carbon steel are most suitable for spot welding. Cast iron can be only welded by Gas welding ( oxyacetylene) with preheating and Post heating technique. TIG welding is also used to weld stainless steel.