The benefits of steel vs. aluminum used to be discussed deep in the bowels of automotive engineering departments. A few engineers and manufacturing experts would deliver articulate and occasionally impassioned speeches arguing one point or another, and then upper management quietly made a decision.

Now the battle has grown far shriller, replete with press releases and news conferences.

And with good reason. The stakes are much higher for both camps, which are suffering from falling revenues, erosion of core non-auto markets and cutthroat global competition. They now are locked into a life-and-death struggle to win the hearts and minds of automakers, whose business could make or break them in the coming decade

On the steel front

Losses: After making steady gains for the past eight years, steel use in the typical family vehicle is predicted to drop 15 lbs. (7 kg) on a per-unit basis. Although hardly catastrophic, the drop is a signal that lightweight alternative materials finally may be pounding a dent in steel's automotive dominance.

Smarter competition: The aluminum industry is becoming more aggressive in its pursuit of automotive business. In early September the Aluminum Assn. trade group announced plans to open a Detroit-based office late this year and create global cooperation among nine national trade associations for automotive aluminum. The moves are seen as important steps to better respond to automotive customer expectations, domestically and internationally. The office announcement comes only a few months after the formation of the Auto Aluminum Alliance, a new partnership between automakers and aluminum producers aimed at pursing ways of increasing use of aluminum in mass-produced vehicles. Both of these moves mirror long-standing steel industry initiatives such as the Auto/Steel Partnership and Automotive Applications Committee, which have helped steelmakers protect their turf.

New contracts: General Motors Corp. recently inked an innovative 10-year, multi-billion dollar agreement to buy aluminum at predictable prices and co-develop new applications with Alcan Aluminum. It also agreed to buy more than $1 billion worth of recycled aluminum over 13 years from another supplier.

On the Aluminum front

Cost pressures: Low U.S. fuel prices and steel's big cost advantage continue to hamper aluminum's bid to take over new applications on mainstream components such as vehicle bodies.

Tough competition: Once arrogant and slow, the steel industry has turned into a fast-moving target. Steel companies have managed to confound the aluminum industry by putting aside their differences and jointly funding projects that contribute to their common good, such as the development of a new type of lightweight steel auto body that can fight the aluminum challenge.

Losses: The aluminum industry would like you to assume that once a part is switched to aluminum it stays that way forever, but in fact many parts are changed back to steel for various reasons, usually cost. Some showcase projects such as an aluminum-intensive crossover vehicle at Ford, code-named D219, also have recently been killed.

The words started flying last summer when the Aluminum Assn. claimed that 1 ton (900 kg) of aluminum in automotive applications in place of steel reduces 20 tons (18 t) of carbon dioxide emissions over the life of an average vehicle, thereby making aluminum a key tool in the fight against global warming.

Officials at the steel industry's trade association, the American Iron and Steel Institute, immediately attacked, claiming the calculations don't include the considerable negative environmental impact of manufacturing huge additional quantities of aluminum for automotive consumption. Smelting primary aluminum - used for body panels and structures - is an environmentally dirty process, AISI points out. Among its drawbacks: it requires massive amounts of electricity, and most of that still comes from CO2-spewing coal-fired power plants.

At the Aluminum Assn.'s annual meeting recently in Detroit, Richard B. Evans, president of the Alcan Global Fabrication Group and president of the Aluminum Assn., called AISI's arguments "emotional, transparently self-serving and less than scientific."

He also declared that in 10 to 15 years "steel will represent less than 50% of automotive structures" and likened current steel proponents to optimistic buggy whip manufacturers in 1899.

That no doubt was a response to an AISI news release pointing out that less than 2% of auto aluminum goes into body structures and closure panels (hoods, decklids, doors). "Nearly 75% of auto aluminum goes into drivetrains and heat exchangers." It points out.

"A common perception created by reports of growth in the use of aluminum by vehicle makers is that aluminum sheet has made large inroads and steel body sheet has borne the brunt of aluminum's increased penetration," says Darryl C. Martin, AISI's senior director of Automotive Applications. "This is not true," he says.

Citing a recent independent study, he says that of the average 248 lbs. (112 kg) of aluminum in today's vehicles, less than 5 lbs. (2.3 kg) is related to the body. "We're very mindful of the gains that aluminum has made in automotive applications, Mr. Martin says. "But we want to be clear that aluminum's gains in sheet applications have been negligible and that steel sheet continues to be vehicle makers' material of choice for body structures and closures." o