Magnesium Die Casting
Casting is a process in which a molten metal is poured into a mould that contains the intended shape. High pressure die casting (HPDC) is the most common method of Magnesium Die Casting and its alloys.
Magnesium is melted at a temperature of 923K and poured into crucibles where it is cooled under high pressure. The cooled magnesium solidifies and takes the shape of the crucible.
Magnesium has an inflexible hexagonal structure at its basic atomic level which makes it difficult to roll, stretch and shape. HPDC overcomes this limitation by offering an alternative, less difficult and faster method for manipulating
Uses of Magnesium casting
Magnesium is increasingly used in automotive and airplane manufacture. This is due to its light weight per unit volume. Casted Magnesium is also used in the manufacture of lightweight car seats, car body and fuselage parts. The use is attributed to Magnesium being the lightest structural metal which can withstand greater column loading per unit weight.
Magnesium and its alloys are being used to manufacture chassis for appliances such as laptops, cameras and phones.
Magnesium castings are also used in the manufacture of power tools such as chain saws, electric drills and electric nail guns. Use in electrical appliances is gaining ground owing to its ability to conduct heat and electricity.
Advantages of high pressure die casting
Magnesium casting offers good finishing characteristics as minute details can be impressed onto the final product. High pressure die casting is more economical compared to other methods of shaping Magnesium.
In this green era, the ability to recycle Magnesium makes High pressure die casting an environmentally friendly process. Magnesium metal is almost 100% recyclable thus reduces industrial junk.
Casted Magnesium alloys have high conductivity. There is marked improvement in the electrical and thermal conduction capabilities in Magnesium alloys making them suitable for use in electrical and thermal appliances.
Magnesium and its alloys can be casted into various shapes suited for different uses; Casting into thin walls can be achieved. Since Magnesium saves on weight without reducing on durability, Magnesium thin walls are relatively stronger and lighter as compared to other metals of the same volume.
It has been noted that molten Magnesium has reduced affinity to iron thus can be casted in iron crucibles with a reduced risk in the final product acquiring iron impurities.
Casted Magnesium is resistant to corrosion by the elements, most notably, is the reduced susceptibility to Hydrogen porosity.
Disadvantages of high pressure die casting
Due to its very high melting point, melting Magnesium is both a dangerous in safety and expensive process. A lot of energy is required to melt the Magnesium thus increasing the cost of production.
Moreover, the very high molten temperature of Magnesium can cause the liquid metal to take some of the iron from the crucible. Acquiring iron from crucible is often undesirable as it would make the final product relatively impure.
Molten Magnesium is more viscous than other metals such as Aluminum. As a result, more pressure is required in the cooling process in attempt to acquire the intended casting detail since cooling is often done under pressure.
To produce Magnesium die casting has high risk than producing Aluminium die casting, Magnesium is easy to get on fire since the ignition point is very low and it is hard to control this. this is why the cost is more expensive than Aluminum die casting.