Investigating the tube production via friction stir extrusion of aluminum chips

Friction stir extrusion (FSE) is one of the friction stir based techniques commonly adopted among the solid state recycling (SSR) category. In the last decade this process was widely explored as one of the most straightforward applications for wire or rod production from recycling metal scraps. Nowadays, the friction stir extrusion techniques have also been investigated as a possible alternative for tube production. In this research, this friction-based process was explored aiming to obtain a consolidated tube by directly processing machining chips. Generally, the FSE setup involves a die, where the metal scraps are collected, and a tool with a designed hole for backward extrusion, but for the case of tube production the setup changes, and the clearance between die and tool becomes the extrusion channel. This process was investigated by varying the vertical load and the rotational speed of the tool, which were directly linked to the pressure and heat generation, respectively. Three parameter combinations were selected, namely cold, warm, and hot conditions. Moreover, a numerical simulation campaign was developed to give an insight into the process’ dynamics and material flow characteristics.