In Situ Detection of Non-metallic Inclusions in Aluminum Melt (1xxx)—Comparison Between a Newly Developed Ultrasonic Technique and LiMCA and PoDFA Method

An ultrasound-based method for the detection of non-metallic inclusions in cast and wrought aluminum melts is being developed. Main objective of the development is to meet the requirements for a sufficiently fast and precise assessment of the present contamination grade in the melt with a handy and comparatively cheap set-up. First trials, using the Liquid Metal Cleanliness Analyzer (LiMCA) and Porous Disk Filtration Analyzer (PoDFA) method for comparison to evaluate the developed system, showed a very good correlation between the ultrasound results and the reference procedures. Defined types of inclusion particles with specific size ranges were introduced into a base aluminum melt with a purity of 99.8%. The settling curves were monitored by LiMCA and the ultrasonic detector. Furthermore, PoDFA samples were taken at certain points in the process. The trials prove the achievement of a detection limit down to a particle size of 20 µm and a particle concentration of less than 1000 particles per kg aluminum melt.