CHELSEA, MICH. - Uncle Sam said he will use a lightweight material for the Supercar he's building, but don't expect that to be a plastic composite. ``As of today, steel will be the main material in the vehicle,'' said Francois J. Castaing, vice president of vehicle engineering for Chrysler Corp.
Castaing - interviewed June 28 at the Chrysler proving ground in Chelsea - is the senior corporate team member in the Partnership for a New Generation of Vehicles. The 18-month-old joint effort of the U.S. government and the Big Three automakers will develop technologies for a new generation of cars with as much as three times the fuel efficiency of today's typical family sedan.
The partnership's Supercar is expected to get 80 miles per gallon in the year 2003.
``Plastic is too costly. We'll use some aluminum but not a lot; it is expensive and hard to form, weld, paint and repair,'' Castaing said.
Another element in the materials picture is the fact steel producers have become more customer friendly, he said.
``Steel companies in the United States for years had a take-it-or-leave-it attitude toward the quality and price of their product. But, in the last five or six years, they've had a change in attitude. Now, they're sponsoring technical research to improve steel and how it is used,'' Castaing said.
``In that period, they've learned how to make it stronger, lighter and better-bonding.''
That research has helped steel remain dominant, reinforcing fundamental qualities that make it attractive to vehicle builders, he said.
Castaing said steel's biggest drawback is weight, but there are great possibilities for reducing weight. Castaing said plastics has its uses, and as an example he points to Chrysler's high-performance, $56,000 Dodge Viper. That car's body is made using resin transfer molding. Viper's production rate is 10 or 15 units a day. In Detroit, an assembly rate four times that is considered desirable high-volume production.
``We've learned a tremendous amount, good and bad, about plastics,'' Castaing said.
The company used plastic fenders last year on some versions of its strong-selling line of LH cars, which includes models such as the Chrysler Concorde and Dodge Intrepid.
``We switched back to steel. We had a hell of a time with plastic. We had trouble with fit. We had trouble under the hot sun as the material moved and made the gap change,'' Castaing said.
Next year, Chrysler will make an unusual move when it introduces a still-secret exterior panel application of sheet molding compound.
``That will be application-driven by specific constraints and the volume will not be too high,'' the engineer said.
He does expect plastic to continue to replace aluminum for intake manifolds for engine air. On the other hand, Castaing said he believes aluminum will gain significantly at the expense of iron castings in engine blocks and heads.
Castaing said of steel, ``It is inexpensive, easy to paint and weld and it resists damage during transport. And, the price has been pretty stable compared to aluminum and plastic, which is derived from oil.''
He said steel's dominance is not likely to change in the next five or even 10 years. That is, however, barring some dramatic change like tougher federal Corporate Average Fuel Economy requirements or another embargo on crude oil shipments to the United States by Arab oil-producing nations.
He said improvement made in forming technology is another reason for steel's bright prospects. Researchers financed by the steel industry are making what Castaing calls ``tremendous improvements in how to use steel.''
Among those improvements he cited include hydroforming, a way of shaping tubing by using hydraulic pressure.
``That's created a wide new field of possibility for us. It's not a question of how much steel you use,'' Castaing said, ``but how you form it and how components are designed.''