Optimization of friction stir back extrusion mechanical properties and productivity of magnesium AZ31-B seamless tubes

Abstract

Friction Stir Back Extrusion (FSBE) is a new sustainable manufacturing process capable of producing fine grained lightweight tubular shapes. The objective of this work is to investigate the impact of rotational speed and feed rate on the mechanical properties, cycle time and power consumption of friction stir back extruded Mg AZ31-B tubes and determine the optimal settings. FSBE experiments and tensile tests were performed to characterize the mechanical properties of the produced tubes. The investigation is conducted utilizing Response Surface Methodology (RSM) and desirability multi-response optimization technique. Results suggest that ultimate tensile strength and toughness are impacted by both rotational speed and feed rate and are more sensitive to speed. However, both process parameters did not show a significant statistical impact on elongation. Optimal parameters for mechanical properties were identified at a rotational speed of 1767 rpm and feed rate of 102 mm/min. The optimal settings to maximize mechanical properties, minimize power consumption, and maximize productivity were 2000 rpm and 116 mm/min.