IMPACT Report Validates Steels Long-Term Future as Material of Choice for Vehicles

DETROIT, MI, March 21, 2001 - A report on Phase I of the IMPACT program, a collaborative effort among industry, government and academia to develop robust, lightweight, dual-use trucks, confirms that substantial weight reductions are possible with higher-strength, low cost steels and optimized design. The report concludes "there is no reason to believe that 25 percent weight reduction represents an upper bound on the long-term weight reductions possible in a steel-based vehicle."

Conversely, the report stated that "there is no reason to believe that aluminum has unique weight reducing properties when used in automobiles and trucks…(and that) the substantially lower variable cost of steel vs. aluminum makes steel the superior choice for high volume production applications."

"Advanced Material Technologies for 21st Century Trucks" (SAE paper #2000-01-3124), authored by representatives of Ford Motor Co., the U.S. Army, Mississippi State University, University of Louisville and a consulting firm, and delivered to the Society of Automotive Engineers (SAE) International Truck & Bus Meeting and Exposition in December 2000, reports on the initial phase of IMPACT (Improved Materials & Powertrain Architectures for 21st Century Trucks).

Phase 1 of the three-phase program validated that cost-effective weight reductions of up to 25 percent are possible using steel "because steel offers the most structural benefit per unit cost," according to the paper. The paper cited "breakthrough material technologies and improved manufacturing processes for steel (that have) demonstrated and validated that strategically removing unneeded mass results in lighter steel components."

Additionally, the paper stated that it is possible to further enhance "desired steel properties needed for vehicle stiffness, strength, impact resistance and crashworthiness."

Phase I, which began in September 1999, comprised defining underlying structural theory for selecting proper materials to reduce vehicle weight in the most efficient, cost effective manner.

Already well underway, Phase 2 consists of designing and building optimized, proprietary full vehicle platform prototypes that achieve up to a 25 percent weight reduction without compromising any customer-driven vehicle attributes. The program is using a current generation Ford F-150 truck as the benchmark vehicle. Phase 3 will extend the work to Ford’s larger F-250 and F-350 versions.

The IMPACT Phase 1 methodology focused on determining the most affordable mix or portfolio of materials to achieve 25 percent weight reduction. It explored "widespread but arguable paradigms" that weight reduction always adds cost to a vehicle and automotive weight reductions of more than 25 percent require use of expensive, non-ferrous materials.

The paper contains substantial discussion comparing inherent properties of steel and aluminum. Aluminum holds an advantage over steel when resistance to buckling is important, such as in aircraft structures. However, automotive structural design is stiffness and strength driven. "It is a complicated design and manufacturing issue, in which the manufacturing problems often dictate the design. There (is not) anything intrinsic in the properties of aluminum (that) automatically give it a weight advantage over steel in ground vehicles.

"Due to the higher variable costs (of aluminum), aluminum intensive vehicles are only feasible in higher price market segments, and aluminum extrusion based structures theoretically may weigh more than optimized steel structures."

Phase 2 of the program will conclude later this year and Phase 3 already has begun. The U.S. Army TACOM, Ford Motor Co. and American Iron and Steel Institute fund IMPACT.

By project’s end the American Iron and Steel Institute (AISI) will have contributed nearly $2.6 million in cash, in-kind services and materials. Other partners include Oak Ridge National Laboratory, Mississippi State University and the University of Louisville.

As it has in its ULSAB UltraLight Steel Auto Body series, the steel industry is contributing cutting edge materials, such as high- and ultra high-strength steels, and advanced process technologies such as tailor welded blanks, laser welding and hydroforming. The steel companies committed to advancing steel’s position include: Bethlehem Steel Corporation, Dofasco Inc., Ispat Inland Inc., LTV Steel Company, National Steel Corporation, Rouge Steel Company, Stelco Inc., U.S. Steel Group, a unit of USX Corporation, WCI Steel, Inc., and Weirton Steel Corporation.

The Automotive Applications Committee (AAC) is a subcommittee of the Market Development Committee of AISI and focuses on advancing the use of steel in the highly competitive automotive market. With offices and staff located in Detroit, cooperation between the automobile and steel industries has been key to its success. This industry cooperation resulted in the formation of the Auto/Steel Partnership, a consortium of DaimlerChrysler, Ford and General Motors and the member companies of the AAC. For more news or information, view the American Iron and Steel Institute/Automotive Applications Committee's website at

American Iron and Steel Institute/
Automotive Applications Committee:

Bethlehem Steel Corporation
Dofasco Inc.
Ispat Inland Inc.
National Steel Corporation
Rouge Steel Company
Stelco Inc.
United States Steel Corporation