Optimizing high-volume ultrasonic melt degassing using synchronized kinematic translation

Abstract

Ultrasonic vibration is a physical processing technique that has been gathering support as an environmentally friendly approach to degas light alloy melts. Since metallic sonotrodes promote melt inclusions due to erosion, ceramic sonotrodes have also been shown as a viable solution for ultrasonic melt degassing in industrial scales. This study shows that resonant ceramic sonotrodes are characterized by a complex low-amplitude radial eigen mode, while particle image velocimetry reveals that their efficiency depends on the angular direction. An approach based on synchronized kinematic translation was designed to optimize the degassing efficiency in ultrasonic approaches, assuring its angle with higher cavitation is always facing the center of the crucible. Results show that this approach can reach lower degassing thresholds (Hmin ¼ 0.13 ml/100 g Al) at higher degassing rates, relatively to both Argon inflation (Hmin ¼ 0.22 ml/100 g Al) and static Ultrasound (Hmin ¼ 0.18 ml/100 g Al) methods. An enhanced grain refinement further supports the hypothesis that promoting a synchronized kinematic translation enhances the ultra sonic degassing efficiency. Considering these results, this approach is suggested as a reliable route to implement efficient ultrasonic degassing techniques in industrial light alloy melt treatment.