Optimization of ultrasonic cavitation processing in the liquid melt flow

Joint 5th International Conference on Advances in Solidification Processes;5th International Symposium on Cutting Edge of Computer Simulation of Solidification, Casting and Refining

土木建筑工程;计算机科学

Subroto, T.^1 ; Eskin, D.G.^1^2 ; Tzanakis, I.^3^4 ; Lebon, G.S.B.^1 ; Miranda, A.^1 ; Pericleous, K.^5

Brunel Centre for Advanced Solidification Technology, Brunel University London, Kingston Lane, Uxbridge

UB8 3PH, United Kingdom^1

Tomsk State University, Tomsk

634050, Russia^2

Faculty of Technology, Design and Environment, Oxford Brookes University, Oxford

OX33 1HX, United Kingdom^3

Department of Materials, University of Oxford, Oxford

OX1 3PH, United Kingdom^4

Computational Science and Engineering Group (CSEG), Department of Mathematics, University of Greenwich, London

SE10 9LS, United Kingdom^5

关键词: Acoustic measurements;    Continuous treatments;    Dendrite fragmentations;    Direct chill casting;    Non-metallic inclusions;    Structure refinements;    Ultrasonic cavitation;    Ultrasonic processing;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/529/1/012050/pdf
DOI  :  10.1088/1757-899X/529/1/012050

来源: IOP

【 摘 要 】

Ultrasonic processing (USP) during direct-chill (DC) casting of light metal alloys is typically applied in the sump of a billet. This approach, though successful for structure refinement and modification, has two main drawbacks: (a) mixture of mechanisms that rely heavily on dendrite fragmentation and (b) a limited volume that can be processed by a single ultrasonic source. We suggest moving the location of USP from the sump to the launder and applying it to the melt flow for continuous treatment. The apparent benefits include: (a) degassing of the melt volume, (b) grain refinement through activation of non-metallic inclusions, fragmentation of primary crystals, and deagglomeration of grain refining substrates, and (c) a possibility to use a single ultrasonic source for processing large melt volumes. To optimize this process with regard to the acoustic intensity and melt residence time in the active cavitation zone, flow modification with baffles as well as informed location of the ultrasonic source are required. In this paper, we demonstrate the results of experimental trials where the degassing degree and grain refinement have been the indicators of the USP efficiency for two aluminium alloys, i.e. LM25 and AA7050. The results are supported by acoustic measurements and computer simulations.