ABSTRACT
This chapter explains the methods that are involved in joining the materials. There are four main types of fusion-welding processes: Arc-welding; Electrical resistance welding; Thermo-chemical welding; and the Radiation welding. With the solid-state welding, pressure brings the interfaces of the surfaces being joined into such close contact that they two fuse together. The Tungsten Inert Gas (TIG) has been developed for welding aluminium and other materials, because of the high quality of welds produced, and it is popular for the precision work in aircraft, atomic engineering and instrument industries. In the Electro-slag welding process, the arc merely initiates the melting process, and the heat is generated by the electrical resistance of the slag, which is sufficiently conductive to permit the current to pass through it from the electrode to the metal pool beneath. Oxyacetylene welding is probably the best known of these, though the Thermit process continues to have its uses.
