Rotary friction welding is a cost-effective method of assembling anything from hand tools to hydraulic piston rods.
Rotary friction welding works in the same way. One metal component is rotated against a fixed component under pressure. Friction between the two parts removes surface oxides and heats the metal in the joint zone to the plastic state. As the parts begin to upset, the metals share electrons and bond to each other. The rotation stops, additional axial force is applied, and the weld is accomplished.