Degassing Kinetics in Secondary Light Alloys for Recycling

초록

Nearly 40 % of magnesium alloy is usually scrapped during die casting process. During recycling the magnesium alloys, hydrogen gas is unavoidably entrapped as gaseous impurities in the final products. Therefore, technologies for both degassing and hydrogen gas analysis are necessarily required. For this purpose, to simulate degassing behavior of hydrogen, theoretical setup for hydrogen removal and a water model experiment were carried out. Hydrogen contents in magnesium alloys was also attempted to be measured by modified vacuum hot extraction instrument(MVHEI). As a result, degassing rates in refining experiments and water model experiments were well matched with prediction values. Argon gas flushing over 500cc/min in 10kg melt lowered hydrogen concentration from over 20ppm to below 10ppm within 30 minutes.