Magnesium alloys are rapidly gaining ground as the lightest structural materials. While in 1995 world production of die-cast magnesium structural parts was only 40.000t, in 2001 magnesium foundries have already shipped approximately 125.000 t, according to International Magnesium Association. At the same time, magnesium prices continue to fall, partially due to growing Chinese supply, which further stimulates magnesium die casting industry. The extraordinary growth in magnesium structural castings is explained by the need of car manufacturers to lower fuel consumption while increasing comfort and safety of cars. Reduction of car weight may be achieved by utilisation of light-weight structural magnesium castings.The advantages of magnesium alloys vs other structural materials may be summarized as follows: ± low density Ð with 1.7 g/cm 3 magnesium is 30 % lighter than aluminium and five times lighter than steel; ± magnesium alloys have higher strength-to-weight and stiffness-to-weight ratios than aluminium or steel;± magnesium alloys have excellent casting properties, which allows for manufacturing of thin-wall, intricate parts; magnesium does not attack steel dies and allows for longer die life;± magnesium alloys have excellent machinability, better than that of other metals;± magnesium alloy part provide good damping capacity and excellent electromagnetic shielding;± development of new, high-purity alloys allowed for improvements in corrosion resistance.Though magnesium castings are usually manufactured using high-pressure die casting method, approximately 1 % of magnesium castings is still manufactured using gravity sand casting method (total world production was estimated as 1500 ton in 2001). Main consumers of magnesium gravity castings are military equipment manufacturers, aeronautic industry and racing car makers.Recent developments in the field of green sand moulding, together with low cost of moulding materials (green sand), high degree of recyclability of moulding materials and high flexibility of green sand moulding process were the key factors, fostering Foundry Institute of Technical University of Freiberg to start an extensive study on sand casting of magnesium alloys. This study focused on two aspects: technology of green sand moulding for magnesium and mechanical properties of magnesium sand cast parts. Since aluminiumcontaining alloys is the most widely used group of magnesium casting alloys, we concentrated on ªclassicº alloy AZ91HP. Key results of this study are presented in this paper.Green Sand Moulding Technology for Magnesium Alloys: Sand casting is one of the most versatile casting methods, allowing greater flexibility of the cast part geometry, relatively low manufacturing costs in comparison to other manufacturing methods and higher productivity. Development of new moulding machines resulted in closer dimensional tolerances, better surface quality and consistent reproducibility of castings. Today, improvements in green sand moulding technology resulted in the same level of dimensional tole...
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