Welding is often a major part of metal fabrication and many formed parts and assemblies will be tack welded together prior to being checked for accuracy and fit.
Welding is a fabrication method which is predominantly about joining metals or thermoplastics by causing coalescence which is commonly achieved by melting the parts, adding a filler material to form the weld pool which, when cooled, becomes a very sturdy joint (the weld). This is different to brazing and soldering which does not induce melting of the initial components but melts a material between the components to form a bond between them.
There are lots of different forms of energy which can be used for welding other than the gas flame most of us recognise being also; laser, electric arc, electron beam, friction or ultrasound. Welding is a skilled operation and requires also several safety precautions to avoid burns, shocks, eye damage, fumes etc.
Starting in Blacksmiths shops with forge welding, shielded metal arc welding is probably the commonest form of welding used today as well as the semi and fully automated processes such as gas metal arc welding (MIG) and flux-cored arc welding and as the technology advances ever onwards so too does the welding systems such as laser beam welding and electron beam welding.
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