Like the strains of an old country song, steel continues to maintain its own melody and momentum.

Because of the shifting market -- from cars to trucks -- and an apparent consumer preference for the material, steel content of the average family vehicle has increased for the sixth straight year.

In addition to the popularity of pickups and sport/utility vehicles (SUVs), which use more sheet metal than cars, other factors adding to steel's growth include the addition of steel reinforcements to improve body rigidity and crashworthiness of other models.

Another reason for steel's continuing momentum is that despite all predictions, studies and forecasts to the contrary, consumers are still "steel crazy." A recent study by American Metal Market suggests that consumers continue to prefer steel over other materials as an auto body material. Responses crossed all boundaries of age, sex, race, income and education level.

Steel's cause has been helped considerably by the American public's insatiable demand for light trucks. Back in 1984, trucks claimed only a 25% share of the overall U.S. vehicle market; through mid-1996 they take 43%. And more than one expert predicts that number will climb to 50% by 2000.

SUVs captured 11.9% of the U.S. light-vehicle volume in 1995, says a Ward's Special Research Report, SUVs: Reshaping the Market -- 1996. The SUV segment will grow to 13.9% of the market by 2000, Ward's forecasts. The middle SUV segment's share of light vehicles will remain flat through 2000, while other SUV subsegments above and below increase their share.

Steel's percentage of the curb weight of a typical U.S.-built vehicle has dropped only 5% since 1976," says Darryl Martin, director-auto applications at the American Iron and Steel Institute (AISI), trade group.

Although the actual pounds-per-car has varied greatly over the past two decades due to downsizing and changes in vehicle body architecture, steel, traditionally has made up the largest percentage of material in cars and trucks. In 1980, 59% of a vehicle's total weight was steel, and from 1990 through 1996, it has held steady at 55%.

In 1990, the curb weight of a typical family vehicle was 3,140 lbs. (1,424 kg). That has climbed to 3,236 lbs. (1,468 kg) in 1996," he says. Jeep Cherokee added 13 lbs. (6 kg) to 3,115 lbs. (1,413 kg), Chevy Lumina gained 42 lbs. (19 kg) to 3,372 lbs. (1,528 kg) and Dodge Intrepid put on 43 lbs. (20 kg) to 3,415 lbs. (1,583.2kg) for 1996.

Very few 1996 models hit the scales smaller or lighter than their 1995 counterparts. In a 1995 WAW survey (WAW--Sept. '1995, p.48), respondents predict steel will hold its percentage of per-car weight through 2000, although 93% of suppliers and 77% of automakers responding suggested that by 2005 steel will lose some share.

American Metal Market and other industry reports point out that steel made up 1,993.5 lbs. (904 kg) of the typical family vehicle in 1980, and iron, copper, brass, aluminum, zinc and plastics made up the other 1,369.5 lbs. (621 kg). Since 1990, steel content sat at 1,717 lbs. (779 kg). By 1994 the number had risen to 1,740 lbs. (789 kg), climbing to 1,781 (808 kg) in 1996.

GM's redesign of its new front-drive minivans in steel -- formerly skinned in plastic sheet molding composite (SMC) -- also has benefited steel.

Not surprisingly, perhaps, the biggest liability of steel is its weight. With the development of the new UltraLight steel auto body (ULSAB) last year by 30 of the world's leading steel companies, the steel industry introduced a new vehicle body concept that is 24% lighter, 34% stronger and $150 less than the body-in-white of a typical family sedan (see WAW -- Sept. '95, p.43).

The ULSAB concept was created to confirm steel's main attributes: inexpensive and strong, easy to form into complex shapes and well suited for high-volume production.

Ford Motor Co., however, has met demands for more options and less weight with a much simpler approach: using more steel -- specifically high-strength steel (HSS) -- on vehicles such as the Windstar minivan. It incorporates the highest number and percentage of HSS parts on any North American vehicle. Employing HSS in its front structure, closures and body-sides, Ford sought to reduce weight through the application of HSS in the body-in-white (BIW) componentry. A rigid body structure is desirable because it provides a smooth, solid ride with freedom from squeaks and rattles.

Steelmakers also have worked to counter competition from other materials through strategic planning and review committees, task forces and cooperative partnerships with automakers.

"We as an individual group (the steel industry) don't assume that steel is there forever," says Doug Tyger, manager-applications engineering for AK Steel and chairman of a communications panel for the AISI.

"Approaches are made to assure steel for the future. We are constantly working to improve steel quality, uniformity, delivery and detail work. We have developed corrosion tests, steel tooling and stamping guidelines. We are committed to improving steel applications in the auto body."

If that sounds like an old refrain, it is. When it comes to steel, the melody lingers on.