ADVANCES IN THE FUNDAMENTALS OF LIQUID METAL PROCESSING AND CASTING OPERATIONS.

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ADVANCES IN THE FUNDAMENTALS OF LIQUID METAL PROCESSING AND CASTING OPERATIONS. The primary aims of this discovery grant are to continue our research on 1) improving the intrinsic quality of all liquid steel melts, and 2) developing a better process, Horizontal Single Belt Casting, to cast aluminium and steel sheets versus the current Direct Chill (DC), and Conventional Continuous Casting (CCC), fixed-mold, technologies. Over the next five years, we plan to further explore the potential for this high productivity, novel-casting process. We wish to study in much greater detail, the role of meniscus movements and oscillations in HSBC processes. For this, we will use Computational Fluid Dynamics analyses of the liquid metal and gas flows within the small meniscus region, about 0.1-1mm thick, that separates our refractory delivery systems for liquid metal flowing from a slot nozzle, onto the horizontally moving, flat belt. We need to evaluate these CFD predictions against experimental findings that are revealed from the quality of the bottom surfaces of cast strips. Bottom strip surfaces can vary from perfect, to poor, depending on the stability of the meniscus, and the suppression of back flows. We will intend to extend this fundamental research to demonstrate HSBC's superior capabilities in casting thin sheets of high entropy light-weight alloys (Alx-Co-Cr-Fe-Ni), bulk metallic glasses (Fe-6B-15C-15Cr-14Mo-2Y), and Fe- 3%Si, and new Fe-6% silicon, electrical steels. These tests will include subsequent rolling of sheet material down to final desired product gauge, and development of suitable mechanical and physical properties. Our second project involves removing exogenous inclusions of all sizes down to the micron size range, from liquid steel, prior to its final solidification. This is important for many steel properties, such as fatigue, surface quality, isotropic properties, etc. Our success over the past five years was to generate micro bubbles in water, for the range of ladle shroud velocities pertaining to generic ladle-tundish-mold facilities used in industry, and using these to remove very small inclusions (20-70 microns diameter). We must now use a low temperature melting point, liquid metal alloy (Cerrolow 136), with physical properties much closer to those of liquid steel (surface tension, wetting angles, density) so that we can quantitatively demonstrate, experimentally, the sizes of micro bubbles that we should be able to produce in liquid steel ladle-tundish-mould systems, for steel velocities ranging from 0.5-5m/s. We aim to re-develop and improve on our original LiMCA (Liquid Metal Cleanliness Analyzer) system, to measure micro bubble sizes in low temperature liquid metals. This will provide quantitative information for forming micro bubbles in commercial steel systems for removal of inclusions, in response to the interest expressed by RTIT/RTMP steelworks in Quebec, and Nippon Steel Corp., Japan.