PUTTING AUTOS ON A STEEL DIET

DETROIT — The days of steel’s dominance in the auto industry surely seemed numbered just a decade ago. At first, the challenger was plastic. In the race to improve fuel economy, lightweight and durable composites were seen as the best replacement for steel on doors, hoods and other body panels.

Next, attention turned to aluminum. Advocates predicted the rust-proof metal would soon come to be as ubiquitous in vehicle frames and panels as it is in beverage cans.

Despite efforts by auto makers to pioneer plastic in such cars as the Pontiac Fiero and aluminum in the Ford Taurus, the materials proved to be both expensive and difficult to manufacture.

Now it is clear that the rumors of steel’s death in the automobile are greatly exaggerated, and steelmakers have committed to an ambitious technology development program to keep their product competitive for the long term.

Steel, the mundane material that evokes images of smoke stacks and molten metal, reigns supreme in today’s vehicles and will continue to for at least the next two decades, experts say.

Despite all the hopes and hype surrounding plastics and aluminum, low-cost and versatile steel makes up about 55% of the average vehicle’s weight, the same percentage as a decade ago. Aluminum and plastics account for about 7% each.

“Now and for the foreseeable future, steel is the material of choice,” said Andy Sherman, a materials specialist in Ford Motor Co.’s research laboratories. “It’s the least expensive and has improved dramatically.”

The battle among materials may be largely unseen by consumers, but it promises to create lighter, safer, more durable and more fuel-efficient vehicles at little, if any, extra cost.

Steel has maintained its position by raising the bar against the competition. The industry has developed new high-strength steels with improved quality and introduced manufacturing techniques that have raised efficiency and lowered costs.

The stakes are enormous. About 30% of the steel made in North America goes to the auto industry, about 14 million tons annually.

Still facing challenges from other materials, the steel industry knows it can’t rest on its laurels. Big steel has undertaken several initiatives to protect its turf. The most visible is the UltraLight Steel Auto Body project, a $24-million effort by 35 of the world’s largest steelmakers to reduce the weight of an auto’s skeletal frame by about a third while also making steel body panels stronger and more dent-resistant.

The steel industry is also studying ways to design and engineer light trucks that weigh 10% to 20% less than today’s sport-utility vehicles and pickups.

The steel consortium retained Porsche Engineering Services, a unit of German sports car maker Porsche, to design and engineer its ultralight auto body. Since the 1930s, Porsche has been recognized for its expertise in engineering.

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With high-strength steels and new manufacturing technologies, Porsche says, it can produce a body for a family-size sedan that is about 150 pounds lighter. It would cost less to produce, require fewer parts, yet be stronger and more rigid.

“Our goal is to prove to our customers the untapped potential of steel in a car,” said Douglas Tyger, manager of applications engineering for AK Steel Holding Corp. of Middletown, Ohio, a member of the consortium.

By next year, the consortium hopes to produce 11 ultralight body frames for testing by auto companies around the world. It then hopes to persuade at least one auto maker to use an ultralight body structure in a high-volume vehicle. Such a project could require a $200-million investment.

High-strength steels--most of them developed in the last decade--are already making their way into autos, including Porsche’s Boxster roadster, which was introduced in the United States this year.

“The Boxster is a lightweight design that uses much of the same technology,” said Robert Koehr, the ultralight program manager for Porsche Engineering. “We don’t have any kind of magic.”

Despite the advancements, steel is strapped to the lingering image of a Rust Belt industry in retreat, which harks back to the battering it took at the hands of foreign competition in the late 1970s. Tens of thousands of workers were laid off and scores of inefficient factories shuttered.

Steel faced its first crisis in the car business with the adoption of fuel economy standards following the 1973 Arab oil embargo. Auto makers searched for alternative materials and designs to reduce vehicle weight. A reduction of 100 pounds of weight roughly translates into a mile-per-gallon gain in fuel efficiency.

The average weight of North American vehicles dropped from 3,761 pounds in 1976 to 3,105 pounds in 1982. During that period, the amount of steel in cars decreased about 30%, as auto makers dropped traditional frames and adopted the unibody concept that required significantly less steel.

In the mid-1980s, plastics emerged as a viable material for body panels such as doors, hoods and trunk lids. The plastic-skinned 1984 Fiero, a sporty two-seater by Pontiac, provided a wake-up call to the steel industry.

“The greatest thing that ever happened to steel was plastics,” said Darryl Martin, automotive director of the American Iron and Steel Institute, a trade group representing the nation’s integrated steel companies. “It kicked us in the ass.”

The result was the formation in 1987 of the Auto/Steel Partnership, a consortium of U.S. steel makers and the Big Three auto manufacturers that began joint research and development on common problems.

Steel was shaken again in 1990 when Ford announced that it would produce 40 aluminum-intensive Taurus and Sable sedans for research. The wide use of aluminum in the popular Taurus prompted steel to form the ultralight consortium that hired Porsche.

Steel had some success winning back business. General Motors Corp.’s minivans, redesigned last year, no longer use plastic panels. Ford’s Taurus still primarily uses steel on its frame and panels.

Still, steel remains the Rodney Dangerfield of the materials world. Its image is so poor that the industry this year launched a five-year, $100-million advertising campaign to boost its appeal.

Consider the Partnership for the Next Generation of Vehicles (PNGV), the so-called supercar program in which the federal government and auto industry are teaming up to produce an affordable 80-mpg family sedan by 2004.

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To achieve the lofty goal of tripling fuel efficiency, PNGV estimated that the vehicle’s weight would have to be reduced by 40%. Aluminum, carbon fibers, plastics and other materials were considered the prime candidates to achieve the targets. Steel wasn’t even mentioned.

“It was felt that steel couldn’t hack it,” recalled Rob Chapman, former chairman of the PNGV task force for the Commerce Department and now a consultant for Rand Corp.

The steel industry was infuriated and demanded a hearing. In a detailed presentation, it claimed it already had the technology to reduce a vehicle’s weight by 17%, would soon achieve 33% and believed a 40% reduction was achievable within a decade.

PNGV relented and ultralight steel was included as an integral part of the project. But skepticism about steel’s long-term role persists. Dick Ziegler, technology manager of the Energy Department’s advanced auto materials program, said steel can offer significant weight savings for today’s cars but is unlikely to meet the PNGV goals.

“The weight savings for ultralight steel just don’t compute to an 80-mpg vehicle,” he said, adding that in his opinion, aluminum has a better potential to meet the weight and cost goals.

Yet steel has shown a surprising resiliency over the years. It has some inherent advantages, being about four times cheaper than aluminum and easier to work with. Most important, it has history on its side--decades of being the auto metal of choice with production tooling and equipment in place.

But with renewed political pressure on auto makers to improve fuel economy, steelmakers know they can’t stand still. The industry knows there is room for improvement, as has been demonstrated by the early findings of the ultralight body project.

The key to that project is the design approach. Traditionally, auto makers have cut weight on a part-by-part basis. But Porsche took a holistic approach, treating the body as an integrated system rather than a collection of parts. This allowed for fewer parts, use of varying thicknesses, different types of steel and advanced manufacturing techniques.

The focus was on high-strength steels that are stronger but lighter than traditional steels. They also absorb more energy, making them safer in crashes. The higher cost of high-strength steel is offset by the reduction in metal used.

The project also emphasizes advanced manufacturing techniques that allow the formation of stronger components. For instance, the roof rail is normally made of several stamped parts. But by using a process known as hydroforming, which uses water under very high pressure to form the rail, the structure can be made as a one-piece tubular unit. Also, new joining techniques, such as adhesive weld bonding and laser welding, allow the production of stronger parts using different gauges and grades of steel.

In the project’s first phase, Porsche estimated that it could cut $150 from the typical $1,100 cost of a steel frame for a five-passenger sedan. In the process, the frame weight would drop by 25% and its strength would increase by a third.

“We showed we could reduce the weight but increase the performance at no higher cost,” said August Hofbauer, chief of Porsche Engineering.

The ultralight project has a downside, however. If it’s successful, auto companies will use less steel. But the alternative is even greater losses of market share to aluminum and plastic.

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Both the aluminum and plastic industries are pouring hundreds of millions of dollars into auto research. The aluminum industry, which says the metal’s use in autos has doubled in the last five years, has made major inroads into engine blocks, radiators and seats. But it is eyeing body frames and panels as well.

“All aluminum companies see the auto sector as an area of growth and opportunity,” said Don McMillan, vice president of automotive for Alcan Aluminum Corp. of Cleveland.

Numerous aluminum concept vehicles have appeared, and this year even a few high-profile niche cars hit the market, including the Audi A8 luxury sedan and the Plymouth Prowler hot-rod wannabe.

While granting that steel has improved, McMillan said aluminum can save even more weight by adopting the technologies used by steel. Aluminum is less dense and as strong steel. That advantage, McMillan said, will win out as the cost of aluminum is reduced and better manufacturing processes are developed. He predicts high-volume models hitting U.S. roads early next century.

But big steel seems undaunted after fending off challengers for 20 years.

“Steel will be hard to displace, because there are still significant weight reductions to be made using steel,” said Peter Peterson, director of automotive marketing for U.S. Steel Group.

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Putting Autos on a Steel Diet

The steel industry, fighting off inroads by aluminum and plastics, has launched an ambitious effort to reduce the weight of a car body by 25% or more. The Ultralight Steel Auto Body project, made up of 35 of the world’s largest steelmakers, is developing skeletal frames that are lighter, stronger and less costly than traditional auto bodies.

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Holistic Design

Treats body structure as an integrated system rather than a collection of individual parts. Means fewer parts, welds and joints and less weight.

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Hydroforming

Advanced manufacturing technique allows the roof rail to be formed as a single high-strength tube rather than from a series of components.

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High-Strength Steels

Stronger than traditional steels and more crash-worthy. Higher cost is offset by lower mass.

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Tailor-Welded Blanks Reduces weight and enhances structural performance in large panels. Allows the joining of different gauges and grades of steels. Needs fewer dies and welds.

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Laser Welding

Allows highly precise joining of steel sheets. Weight is reduced because there is less material overlap.

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Steel Sandwiches

Spare tire tub is made of polypropylene sandwiched between thin sheets of high-strength steel. Design is 50% lighter than a homogenous steel tub.

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Source: American Iron and Steel Institute