Changes in Properties of Ingot Recycled from Die-cast Components made of AZ 91 D Magnesium Alloy with Paint Finishing by Manganese Addition

Abstract

A newly recycling process for video camera components of AZ 91 D magnesium alloy used for professional market was developed by melting and casting processes in order to satisfy the JIS specifications for recycled AZ 91 D magnesium alloy ingot. Various quantities of Mn were added to the melt in order to avoid contamination by impurities such as Fe, Ni and Cr from paints. Composition analysis and mechanical properties and corrosion resistance of the recycled ingots were also examined. Recovery ratio of the recycled ingots is in the range of 60 % to 75 %. Chemical composition and tensile properties of the recycled ingot with Mn addition of more than 0.23 % is satisfied by JIS specification except for Cu content. Tensile strength and 0.2 % proof stress of the recycled ingots increase with increasing Mn content. The recycled specimens with Mn addition of more than 0.23 % almost exhibit the same level of corrosion resistance as the virgin ingot of AZ 91 D magnesium alloy.