ABSTRACT
In all friction-assisted processes, heat is generated by friction and utilized to join similar and dissimilar materials or to modify the microstructure and chemical composition of metals without melting. Rotational friction welding is possible with the components which possess rotational symmetry. Angular reciprocation between the surfaces to be joined also generates friction and raises the required temperature at the interface. Several research groups have done a considerable amount of contribution in developing solid-state welding techniques with the evolution of friction welding. Based on the basic principles of friction stir welding, friction stir processing technique was developed to modify the microstructure of metals. Friction surfacing is another method developed to coat the surface with a metal with less dilution based on the friction – heat generation principle. Development of friction stir spot welding has offered several advantages to join sheets and plates without melting the base materials.
