2015年6月19日星期五

Better than Steel: Magnesium Alloys in the Automotive Industry


For years, the auto industry has touted the use of and need for steel in trucks, cars, and sport utility vehicles. Then, the public began asking for a more fuel efficient, less emissive, and cheaper vehicle. Newer, more environmentally sound cars are answering this call. Surprisingly, they have accomplished this without the use of the industry's beloved steel. The kicker is that consumers didn't notice the material switch.

The Mysterious Steel Substitute
Contrary to belief, magnesium alloys are much lighter than steel, cost less to fabricate, and make cars much more fuel efficient and "green". The alloy is all of the following:

A quarter of the weight of steel, but just as strong. In fact, magnesium is the lightest of all metals used to build cars, buildings, and other structures like bridges.
More impact resistant. Magnesium alloys absorb more of the impact's energy. They are therefore more resistant to dents.
The dampening capacity or ability to reduce noise and vibration is also much higher than that of steel.
Magnesium is less rigid and bends easier than steel, making it easier to fabricate.
The alloy isn't actually new. It was discovered in 1755 by Joseph Black and isolated in 1808. The search for a more efficient and abundant material has led researchers to experiment with magnesium alloys in the place of the more traditional materials like steel that doesn't perform as expected. The aforementioned factors have made the alloy a newfangled contraption in the auto industry.
The Faces of Magnesium in Automotives
Some of the first uses for magnesium in automotives were inside the car. Die cast steering columns, engine blocks, and chassis were just some of the uses for the alloy in cars. The vehicles were much lighter, used less gas, and had less emission as a result. Eventually, seat frames, dash panels, and the track that held the sunroof were also cast from magnesium. Naturally, the next step became taking the alloy to the outside of the car.

Magnesium alloy sheeting made roof panels, hoods, oil pans and other outer elements of the common car lighter, stronger, and more resistant to impact. Expense was a concern for the die casting process, but the sheeting is less expensive because it requires less compression force to create, allows for parts consolidation and simpler designs. In addition, magnesium alloys have a shrinkage rate that is very predictable and less energy is required to make the sheets.

The alloys thus a step above steel, without a sacrifice in safety. One of the common misconceptions is that cars made from magnesium alloy as opposed to steel are less safe. You now know that the opposite is true. Magnesium alloys may just replace steel completely in the future.
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