CHICAGO Advanced high-strength steels (AHSS) are now the fastest-growing materials used in automotive production, and the industry has doubled the number of lightweight grades it produces over the past 10 yearsincluding one that is lighter than plastic, John Surma said on behalf of the Steel Market Development Institute (SMDI).
The 2013 North American Car and Truck of the Year award winnersthe Cadillac ATS and Dodge Ram 1500"both feature an extensive amount of these new steels," Surma, chairman and chief executive officer of Pittsburgh-based U.S. Steel Corp., said during an Automotive Press Association event April 11.
Meanwhile, the 2013 Ford Fusion features the worlds first hydroformed steel tube used as a B-pillar, and the 2013 Kia Optima, named Road & Travel Magazines International Car of the Year, is made with new steel grades to enhance structural integrity, stiffness and ride quality, Surma said.
Similarly, Chevrolets 2014 Silverado 1500 full-size pickup truck features AHSS in its main rails and cross members, with hydroformed elements for reduced mass and greater strength, and nearly two-thirds of the truck cab structure is made from AHSS, Surma said.
Todays higher-strength steel grades are as much as five times stronger than their predecessors and can yield parts that are as much as 39 percent lighter than their traditional counterparts. Such advances will be key to reaching the goal of 54.5 miles per gallon by 2025, Surma said.
In addition, the higher formability of AHSS gives auto designers more latitude to develop weight-reducing shapes and aerodynamic designs, which aid in achieving greater fuel economy, Surma said. AHSS also can help improve structural safety.
In February 2013, the Steel Market Development Institute, the Auto/Steel Partnership and the U.S. Automotive Materials Partnership "began an aggressive collaborative project" with the U.S. Energy Department, five universities and Pacific Northwest National Laboratory to develop integrated computer models that will help create the next generation of advanced steel grades, Surma said.
Today, AHSS is successfully used in vehicle skeletons and chassis and body in white. The next step is closures, he said.
"Let me throw in one last lightweighting fact," Surma added. "There is a current-production-model vehicle that has a plastic fuel tank. The SMDI team saw this particular part as a design challenge. The result? A steel tank that is 9- to 16-percent lighter than the plastic version on the car and cost-neutral," he said. "Steel lighter than plastic: Im pretty sure that is not a headline you were expecting to hear from me today, but feel free to use it in your publications. Our industry will not mind."