Forget the claims that the all-aluminum automotive future was “right around the corner” and that “steel’s days are numbered.” The fact is that steel has created a number of new grades promising greater strength and lightness, most OEMs aren’t about to incur the costs associated with tearing up their assembly plants in order to switch materials, and steel is a known quantity well supported within the engineering ranks. Even the tightening of fuel economy standards probably won’t start a wholesale stampeded to aluminum as automakers chase every mile per gallon in order to reach the requirements. So why is Lloyd “Buddy” Stemple, chairman, Aluminum Association Auto and Light Truck Group and v.p. and general manager of Specialty Products at aluminum supplier Novelis (Cleveland, OH; www.novelis.com) smiling?
“Worldwide, aluminum use in cars and light trucks has grown uninterrupted for the past 33 years,” he says, “to an average of 327 lb. per vehicle. And while its use in the vehicle structure has lagged behind, we see that demand rising to 417 lb. per vehicle by 2015.” That’s because the industry backed away from its “aluminum or nothing” rhetoric and pursued a strategy whereby it could peacefully coexist with other materials, and grab a bigger piece of the pie in the bargain. Take, for example, SUVs and light trucks. When rollover concerns plagued this segment, the aluminum industry stepped up with studies that showed how an aluminum upper structure could lower the center of gravity of these vehicles, and help reduce rollovers. OEMs began asking for more information with the result that the first examples of this hybrid structure are nearing production.
When automakers began taking their first steps toward meeting the tougher CAFE standards, the aluminum industry didn’t rush in with aluminum-intensive vehicle designs, it showed OEMs how they could take a step-change approach by increasing the material’s use in powertrains and suspensions, and adopting aluminum engine cradles. “The greatest growth potential in the next few years,” says Stemple, “is in the closure panels–doors, roof, hood, and decklid.” Only 18% of the hoods on North American cars are made from aluminum today, and none of the roofs or doors. European automakers have begun switching these panels over, and Stemple believes U.S. automakers will follow as they update existing vehicles and introduce new ones. However, though that change is relatively easy to make, it will come to a relatively swift end as the saturation point is reached. That’s when he believes automakers will begin the move toward more aluminum in the vehicle structure.
“Even with the shift to alternative fuels and drivetrains, the gains in fuel economy and reductions in CO2 emissions will begin to slow,” says Stemple, “and the consumer will be looking for those vehicles that give the greatest return without adversely affecting vehicle performance.” By removing 30% of the weight from the structure while supporting further secondary weight savings, Stemple believes aluminum will move the to the top of the OEM materials consideration list for both cars and light trucks. However, the turnover in the industry as it downsizes could alter this scenario. “I had senior engineers at a car company call and ask if it was possible to build vehicle structures out of aluminum, and–if so–would it be possible to come and talk to them about it,” he says incredulously. Just another example, perhaps, of why adoption of aluminum vehicle structures will be an evolutionary, not revolutionary, process.—CAS