A new design that uses advanced high-strength steel lops 30 percent of the weight off a car's twist-beam rear suspension, to lighten the load for automakers who are racing to meet much higher gas mileage standards.
The Steel Market Development Institute, the business unit of American Iron and Steel Institute, recently released a study that found it was possible to slice nearly a third off the mass of the suspension, also known as a torsion-beam axle, at a much lower cost than designs using alternative materials.
Steelmakers are designing new lightweight car parts so that car makers won't come up with designs that involve aluminum, carbon fiber alloy, or other alternate metals. The pressure is on to shave weight, and fast.
By 2025, cars and pickup trucks will have to get an average of 54.4 miles per gallon, almost double the current standard. The U.S. Environmental Protection Agency announced the new requirements last year, and it triggered a battle between steel, aluminum and other metals for market share.
Steel has long been the most dominant material in cars, accounting for an average of 60 percent of the weight. Aluminum makers say the only way for cars to go on enough of a crash diet to meet the rigorous new emissions is — surprise — by using more aluminum, which currently makes up an average of 8 percent of a vehicles weight. Consultant Ducker Worldwide did a survey that found automakers will likely double the amount of a vehicle's curb weight by 2025.
Industry advocate the Aluminum Transportation Group, for instance, recently unveiled a study that found that an all-aluminum vehicle would shed more than 40 percent of the body mass and increase fuel economy by 18 percent. The lighter but more expensive metal has made inroads, and is used much more in the new Ford Mustang. The muscle car already had an aluminum hood and added aluminum front fenders that weigh 200 pounds less.
Steelmakers are fighting to maintain their market share by making lighter, stronger steels and reimagining car parts to make them leaner. The Steel Market Development Institute, with financial backing from Detroit automakers, hired Canada-based Multmatic Inc. to develop a lightweight steel twist beam that was 15 to 25 percent lighter and cost less than alternative metals.
Multmatic found that a "U-beam" design that used advanced steel could achieve even greater weight savings, while raising the cost by only 15 percent.
"With fuel economy regulations increasing rapidly, automakers are looking for every way they can to take weight out of vehicles," said Ronald Krupitzer, vice president for the automotive market. "The lightweight steel twist beam project is a great example of how currently available advanced steel technologies enable aggressive weight savings in the vehicle's suspension, thus enabling better fuel economy for the automakers and the consumer."