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Magnesium - the lightest of all the commonly used metals, is increasing in automotive applications. When Sir Humphrey Davy isolated magnesium, he found its major advantages - it has only one-quarter the mass of steel and two-thirds the mass of aluminum. Magnesium can be machined faster with less wear and tear on casting tools and has the best strength-to-weight ratio of any of the commonly used structural metals. Magnesium is dimensionally stable because of its consistent shrink rate, and close casting and machining tolerances can be held without stress relief. The material is progressively heated in the barrel from a solid state to a uniform, semi-solid state under tightly controlled conditions. After the material has achieved a predetermined shot size, it is injected at very high pressure and speed into the vacuumized mold cavity. Molded parts are automatically removed. In a few words we can draw a general conclusion that magnesium is better way for metallurgy than aluminum and steel. Production automotive magnesium components are predominantly used in interior applications, such as steering column brackets, instrument panels, seat frames, steering wheels, ashtray doors, sunroof track assemblies, and mounting structures for compact disc/cassette players.
Commercially magnesium became part of automotive industry in 1936 when Volkswagen Beetle was introduced. In 1957 a Corvette SS, designed for racing, was constructed with magnesium body panels. Magnesium was used by Volkswagen in car engine components, too. Porsche used magnesium alloy for its engine blocks. With the necessary technological advantages in magnesium alloy performance being made in 1980's middle and the continuous drive to minimize weight and fuel consumption gave to magnesium industry good start. All these show in 1990 some kinds of vehicle consisted of 1.4 kg (3 lb) of magnesium. After that, ten years later they composed about 3.6 kg (8 lb) of magnesium. Future applications may expand to high-temperature areas under the hood, such as automatic transmission cases and engine components. In 1996, Ford invested in the Australian Magnesium Corp. (AMC) to ensure an affordable and reliable source of magnesium. Starting in 2002, Ford projects show that magnesium is from 2.3 kg (5 lb) per vehicle today to equaling current aluminum composition levels of about 113 kg (250 lb) per vehicle over the next two decades. They increase the using of magnesium and new projects say the using of the metal is around 40,000 to 50,000 t in the 2004/2005 for body structures as well as instrument panel structures. BMW turn to magnesium, too. In their BMW engine uses of aluminum alloy insert for the cylinder walls and cooling jackets is surrounded by a high temperature magnesium alloy AJ62A.
The application of magnesium AE44 alloy in the 2006 has advanced the technology of designing robust automotive parts in magnesium.
Automobile industry nowadays used new magnesium and aluminum wheels. Magnesium wheels are easier for making. As previously arranged by the designers, the flow of the metal in the mould is directed during deformation (the flow direction of the metal) via fibers arranged as orthogonally as possible with respect to the direction of the load acting on the wheel, and via the hydraulic pressure exerted, it produces very compact ordered metal molecules that maximize the final mechanical strength of the wheel. All the working conditions are optimal for obtaining the ideal cast item and avoiding any oxidation: casting temperature and speed, ambient conditions and surrounding climate. Today that technology becomes more and more popular because of its high quality, high strength, and cost effective.
The motor-sport industry worldwide has long recognized the advantages to be gained from using the sand cast high alloys originally developed for the aerospace industry.
Source: magnesium-elektron.com
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