Emissions mandates are causing some automakers to question using steel, but swapping materials can add costs
February 2012- From a vehicle’s inception on the drawing board, to a concept car in an auto show display and finally as a product on a mass-produced assembly line, each step of a vehicle’s journey leaves a carbon footprint. Once the car leaves the factory line and the dealership lot, it continues to have an impact, running on fuel and wearing down roadways. More than ever before, automakers are being challenged to sell emissions-friendly vehicles that are as environmentally friendly to produce as they are while driving on the road. Although some automakers tout the need to use less steel and opt for lighter materials, those in the steel industry make their case for why steel is an optimal choice for tomorrow’s vehicles.
Up until 2012, U.S. Corporate Average Fuel Economy (CAFE) regulations have remained stagnant, says Ronald Krupitzer, vice president of Steel Market Development Institute, Southfield, Mich. “We have had continuous growth in technology and vehicle growth structure. Today’s vehicles are definitely stronger and more efficient, but there hasn’t been this same regulatory pressure to introduce other technologies as there is now until 2025.”
The most-recent legislation regarding fuel economy began in January 2009, raising the industry-wide mile-per-gallon to 27.3 miles, estimated to reduce carbon dioxide emissions by 8.3 million metric tons. In May 2009, President Barack Obama revisited the issue, proposing a new national fuel-economy program that takes on uniform federal standards to regulate both fuel economy as well as greenhouse emissions from vehicle models in 2012 through 2016.
Krupitzer refers to President Obama’s endeavors in July 2011, in which 13 large automakers agreed to support the tighter standard voluntarily. The arrangement would increase fuel economy to 54.5 miles per gallon for cars and light-duty trucks by model year 2025. Krupitzer likened the dramatic changes to what occurred in the United States during the 1970s, when the first CAFE law prompted companies to make smaller cars during the oil embargo. “The reduction of vehicle size happened for about 10 to 15 years,” he says. “It had a big effect on how we built cars and trucks back then.
“It was the first time we tried the idea of using high-strength steel, making vehicles more structurally efficient,” he continues. “We classified those new grades as high-strength low-alloy steels. It was exactly the same material we used for arctic pipe lines. [It was] easy to weld and fit into the manufacturing processes.”
Not easier being green
The development of the latest electrically powered vehicles was reviewed in an engineering study called FutureSteelVehicle (FSV) released by WorldAutoSteel, the automotive group of the World Steel Association, and SMDI in May 2011 and funded by 17 global steel companies. The results showed “we could take more weight out and use more advanced steel to make the vehicles lighter than in the past,” Krupitzer says, adding the study was unique because it not only addressed lighter steel but also the means companies use when manufacturing more emissions-friendly vehicles.
“[If a] manufacturer is looking to not burn a lot of fuel with a fuel-efficient vehicle, it also cannot rob us of our natural resources or emissions to make it—it would be counterproductive if to build the car it took so much energy and emissions in order to build a lightweight vehicle that in the end, it resulted in more total emissions and it couldn’t even be recycled,” Krupitzer says.
He warns that swapping materials could be more costly in the long-run. “This FSV project could allow us to save up to 35 percent of the mass of previous steel-made vehicles compared to 25 percent, which is what we have saved using these steels for the last 10 years.”
“Less steel is used because you’re able to take weight out by making parts thinner,” he continues. “So even though you’re spending more per ton, it costs less because you’re not using as much.” Krupitzer says steel is already in mass production and pursuing the means to manufacture and procure alternative materials to steel would result in significant ecological impact and cost.
“We have all the raw materials we need for these new steels,” Krupitzer says. “But it’s the combination of chemistry and processing that makes each steel unique. Today’s steel is [much more advanced] than steel 10 years ago.” Krupitzer says today’s steel engineers control microstructures as well as the strength and forming properties of steel. “We didn’t have the technology years ago; it took a lot of research. It took us from 2002 when we first started working with companies such as GM and Chrysler to grow AHSS applications. Progress has been incremental.
“There’s a lot [more research] to be done,” he continues. “We have to change the ways we build the dies because [today’s steel] is so strong it tends to wear out the dies. We have to manage these new stronger steels, which have new rules attached.”
It’s not as simple as swapping steel for aluminum, according to Krupitzer. “A car company would have to change its body shop, [for example] spot welding might be eliminated. [The] cost for production would go up while production rates would suffer,” he says. “Our hope is we can continue this AHSS development, support production and offer low-cost steel.” Krupitzer says steel’s “inherent recyclability and low initial energy of manufacturing” is also beneficial in keeping emissions low.
Krupitzer warns that today’s battery-powered vehicle manufacturers “cannot say these electric cars are totally green even though they use no gas,” he says. “Because it requires quite a bit of emissions to put the battery in the car. Unless you account for that, you’re not really managing total emissions.” MM