DETROIT - High-strength steel can by used to make car bodies 25 percent lighter. Although the steel costs more, the bodies don't, because less steel is required, says an international consortium of 35 steel companies.
Today, no more than 20 percent of a car's body consists of high-strength steels, but these make up 90 percent of the bodies developed by the UltraLight Steel Auto Body consortium.
The ULSAB has spent $22 million on its project, designed to persuade carmakers to keep using steel and not switch to aluminum or plastic.
Earlier this month, ULSAB displayed the bodies at the Geneva auto show, in Michigan, and in Australia.
'We have shown that lightweight and steel are not an oxymoron,' said Robert Darnall, president of Inland Steel Industries Inc. at the Southfield demonstration. 'Now we want to take weight reduction to the next level, and test the true potential of steel. We want to expand the envelope even further.'
The steel companies say their lightweight bodies could be produced for roughly the same cost as a current car body. ULSAB estimates that manufacturing and assembly costs total $947 per body, assuming production of 225,000 units annually.
'This is a very efficient body structure,' said Ron Hughes, manager of technical affairs at Rouge Steel Co.
Steel is now being considered a useful material in the US government-industry research program, Partnership for a New Generation of Vehicles. PNGV aims at making a mid-sized car that achieves 80 miles per gallon, which is equivalent to the European target of three liters of fuel per 100km.
ULSAB's body in white weighs 201kg, about 25 percent less than if made with conventional materials and processes.
Fewer parts were used because the body was treated as an integrated system, rather than a welded assembly of individual stampings.
Working with Porsche Engineering Services, the steel companies also made the most of emerging manufacturing technologies, such as laser welding, hydroforming and tailor-welded blanks.
The materials competition in the future will not be a winner-take-all contest, said Allan Murray, Ford's technical director for the Partnership for a New Generation of Vehicles. 'Our vehicles of the future are probably going to include a range of materials,' he said. 'We are looking at ways of using them as efficiently as possible.'
In an extension of the ULSAB project, steel companies are conducting a study of exterior body panels. And last year, the American Iron and Steel Institute did a study on reducing the weight of pickups and sport-utilities.
To remain dominant, 'steel as a material must be a fast-moving, agile target,' said Andrew Starkey, the Institute's president. 'I guarantee you that when steel has an application, someone is trying to take it away from us.'