DETROIT – Lighter-weight alternatives are putting unprecedented pressure on steel as fuel-economy rules tighten, but a top industry executive predicts steel will remain the dominant automotive material for the foreseeable future.

John Surma, CEO of United States Steel, tells the Automotive Press Association here that steel’s adaptability, low cost and environmental friendliness will allow the material to outperform competitors well past 2025 when auto maker fleets are required to hit 54.5 mpg (4.3 L/100 km). However, competitors, especially the Aluminum Association, aluminum’s trade group, dispute his claims.

The Aluminum Association points to a study by the highly regarded Ducker Worldwide research group forecasting automotive use of aluminum to increase from 327 lbs. (148 kg) in 2009 to 550 lbs. (249 kg) in 2025 while steel use slides downward.

The trade group also quotes aWardsAuto story in which a Honda body engineer says, “We’re approaching the practical limits of the application of high-strength steels…”

Speaking to the APA on behalf of the Steel Market Development Institute, a steel industry trade group, Surma brushes off gains competitive materials are making in various new vehicles and applications as typical of inter-material competition that has been going on since the auto industry began.

Despite forecasts that steel’s percentage of a typical light vehicle by weight will decline precipitously by 2025, Surma points out steel’s demise has been wrongly predicted since at least 1953, when an automotive magazine said iron and steel soon would be overrun by aluminum, magnesium and plastics.

Surveys of automotive engineers and designers by WardsAuto publications in the 1980s and 1990s also predicted steel’s role would be diminished by alternative materials. Instead, steel’s percentage of vehicle weight has remained steady at more than 50% for decades.

Aluminum, magnesium, plastics and advanced composites all have made gains over the years, but most of these gains have come at the expense of materials other than steel, such as cast iron and zinc die castings.      

Steel continues to thrive because critics and competitors underestimate the material’s and steel industry’s ability to evolve, Surma says. Critics who doubt steel’s ability to be competitive in 2025 are looking at the material as it exists now, not where it is going, he adds.

Steel has survived because the industry has made massive improvements in cost and technology, Surma says. “I believe the steel industry, in partnership with the auto industry, has done more to improve and enhance steel’s properties to meet auto makers’ needs for lightweighting, safety and cost in the past 10 years than in the previous 100 years,” he says.

As an example, Surma says U.S. Steel and its partner, Kobe Steel, are commissioning a new $400 million annealing line designed to anticipate the automotive industry’s needs. The new line will process the next generation of advanced high-strength steels with formability that will exceed the current range of products.

In addition to being a fraction of the cost of the competition, steel’s unique chemical and physical properties allow it to be formed into ever more lightweight structures, Surma says, adding that new steel grades are as much as five times stronger than their predecessors and can be formed into parts that are as much as 39% lighter than parts made from traditional steels.

These new advanced high-strength steels can reduce vehicle weight at almost no additional cost, while using aluminum to chop weight costs an extra $2.75 per pound and carbon fiber costs more than $7.00 per pound, Surma says.

As contentious as the argument is between steel and aluminum over engineering properties, the debate is even more heated over the environmental benefits of steel compared with aluminum.

Surma and the steel industry argue their material is the greenest because the steel making process emits one-twentieth to one-fifth the amount of greenhouse gases produced when manufacturing materials such as aluminum and carbon fiber.

However, the Aluminum Association counters that looking only at manufacturing emissions is “cherry picking.” An independent report by U.S., Canadian and Chinese governments says aluminum has the lowest total carbon footprint when the vehicle usage stage is included in the evaluation, the Aluminum Association says.