Their are many benefits when we use FSW in various material but using FSW technique on aluminium alloy is the most suited technique.
1. when we talk about the mechanical properties FSW joints has better tensile strength, micro hardness and very refined micro structure which can't be achieved by conventional fusion welding and maximum time fusion welding gives you the defect on the joint.
2. regarding the cost it can be say that FSW has a very low weld cost compare to the other welding procedure because the procedure can be done on the milling machines it self.
3. it create defect free joints and improve the quality of the joint dramatically.
4. FSW doesn't emit harmful gases that's why FSW is also known as green manufacturing procedure.
There is a Russian patent 195846 by Yu.V Klimenko as of 1967 which describes friction stir welding as a welding by a rotating tool introduced between two workpieces
Friction stir welding (FSW) is a solid-state joining process that offers a number of advantages over conventional fusion welding techniques for joining DSS.
Benefits of FSW over fusion welding
(i) FSW is narrower than Fusion welded joints welded joints.
(ii) Friction stir welding is an excellent method of joining for aluminium. Friction stir welds show resistance to stress corrosion cracking (SCC) due to the low heat input of the process and its stability and its ability to dissolve hardening precipitates.
(iii) FSW has been especially useful in creating long and wide structural aluminium panels for industries such as marine, offshore and transportation.
(iv) FSW eliminates most of the advisable effects associated with resolidification inherent to conventional fusion welding. FSW displays less variability in tensile strength in the as-welded condition.
As the base metals can be joined in the solid state during FSW, the joints obtained will have various advantages over joints those produced using traditional welding methods. These advantages include, good quality joint without any defects, improved mechanical properties, reduced residual stresses and less distortion. FSW produce economic joints due to lower consumption of power, no need of joint edge preparation and also no gas shielding is required unlike in conventional welding methods. In addition, the FSW do not produce the arc flash, fumes, spatter, and pollution free which is associated with most of the fusion welding methods. Due to these reasons, for many of the manufacturers FSW process has become an attractive welding process.
Joining of aluminum alloys like 2xxx and 7xxx series is not possible using fusion welding. The copper content in these alloys results solidification cracks. So these kind of heat treatable alloys can be welding only through solid state metal joining process like friction stir welding
As the question suggests that non conventional welding which signifies that it has not so advanced that which makes it compatible to all field of study, while the friction stir welding is the solid state welding which have the capability to avoid and eliminate the problems related to the conventional processes by without melting the base alloy. Moreover, for mass production nowadays the conventional processes were not utilized than FSW.