In FSW process, the joining of the material is produced by the friction heating of a rotating shoulder on the top surface of ... the joint and the mixing of the material in the plastic state due to a rotating tool inserted along the forming welding seam. The generated frictional heat between the tool and the workpiece causes the stirred material to soften without melting. As the tool is moved forward, the probe inside the material lead the plasticised material to the rear, involving that material in a dynamic recrystallization of the base material. Fixed Pin technology is used in straight weld where start and end of the welding seam can be removed, Bobbin Tool is used in straight weld where weld high axial reaction forces are not allowed, Retractable Pin is used when is necessary to perform closed loop weld. read more