Dr. Chandan Deep Singh & Kanwaljeet Singh 
Influence of tool pin profile on single sided friction stir welded joint (AA6061) [EPUB ebook] 

Friction welding is a solid state joining process used for joining of different metals that provides similar welding properties as like parent metal properties. In this welding process no filler metal is required and thus it’s a emissions less process. In this experiment for the purpose to joining of pieces include the generation of heat with the help of friction. Due to this pressure with variable speeds the tool moves on the work piece for joining of two metals. The soft layer of material will move out and angular movement starts during this process.