Degassing of Aluminum Alloy Melts by High Shear Melt Conditioning Technology: An Overview

Abstract

The search for more efficient methods for degassing aluminum alloy melts has always been of great interest for the metal industry because the presence of hydrogen and oxides in the melts’ prior casting was detrimental to the integrity and properties of the final products. In this work, we present an overview of the progress and key findings from the research and development of an innovative High Shear Melt Conditioning (HSMC) degassing technology during the Liquid Metal Engineering (LiME) Research Hub project. Compared to conventional rotary degassing, this novel technique was capable of working at higher rotor speeds to efficiently break and disperse the naturally occurring oxide bifilms in the melt and to capture and disperse each supplied inert gas bubble into many tiny bubbles throughout the whole melt. This resulted in the elimination of the need to degas fluxes to remove the oxides in the melt, the reduction in the gas flow required to reach the same level of hydrogen removal rate, and the minimization of the regassing effect after processing. The increased process efficiency allowed for reduced melt processing costs and, at the same time, improved the melt quality, which resulted in fewer defects and improved mechanical properties.

Keywords

• aluminum
• high shear melt conditioning
• degassing
• oxide bifilm
• hydrogen
• recycling