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Metal wars

Article-Metal wars

Metal wars

Make it lighter, cheaper, and easier to process. These are the major challenges faced by all materials producers, as they vie for a bigger piece of the materials pie in the lucrative and viciously competitive automotive marketplace.

The stakes are so high, in fact, that steel and aluminum producers have had at least one major skirmish over their efforts to influence automakers to use more of their products. To wit, the American Iron and Steel Institute (AISI) recently made headlines citing an MIT study that found aluminum-intensive vehicles fall short of environmental claims.

Compared to the UltraLight Steel Auto Body (ULSAB), an on-going project being pushed by AISI, the MIT report notes that it would take "32 to 38 years of driving aluminum-intensive vehicles to offset the amount of carbon dioxide (CO2) put into the atmosphere by the production of aluminum needed to build those vehicles." The research called into question the aluminum industry's claim that a one-ton increase in the use of aluminum in automotive applications in place of steel would reduce CO2 emissions by 20 tons over the life of an average vehicle. The study's authors argued that in examining the relative environmental merits of alternative vehicle designs, the total fleet must be considered in any life cycle analysis, as opposed to a single vehicle.

"The MIT study strongly suggests that a large-scale shift to aluminum-intensive vehicles could make the carbon dioxide problem worse not better," asserts Paul Wilhelm, president of USX-U.S. Steel Group.

Despite intense competition, steel remains the dominant material in cars today.

The American Aluminum Association quickly countered AISI's challenge. "We are surprised at the combative and counter-productive charges leveled by the steel industry regarding the benefits of choosing high-strength, lightweight aluminum over steel for automotive applications," says J. Stephen Larkin, the association's president.

"Contrary to what the steel industry is claiming, it is documented that one pound of aluminum, replacing two pounds of steel to lightweight a vehicle, can save 20 pounds of CO2 over its lifetime," Larkin adds. "This information has as its base a report by the International Primary Aluminum Institute, which used peer-reviewed data compiled in accordance with ISO standards to draw its conclusions."

Feuding aside, both ANSI and the Aluminum Association are each involved with several programs that address many of the materials challenges faced by the auto industry. Here's a look at some of the key initiatives:

Steel's stance. The steel industry has many on-going programs designed to advance automotive steel design. They include the ULSAB (UltraLight Steel Auto Body) and LTS (Light Truck Study) projects. Both, says Martin, have shown the significant weight-reduction and performance-improvement potential of automotive sheet steel. For example, ULSAB has demonstrated a weight reduction of the body structure of up to 36%, compared to benchmarked vehicles, with a substantial improvement in performance at no increase in cost.

Building on the success of ULSAB, the steel industry is now aiming at the Partnership for a New Generation of Vehicles (PNGV) target of a 2,000-lb, curb-weight vehicle that gets up to 80 mpg. "The new project seeks to demonstrate and communicate the capabilities of the industry to meet society's demand for safe, affordable, and environmentally responsible vehicles for the 21st Century," Martin notes.

The steel industry hopes to accomplish at least a part of that goal through a new consortium formed to oversee an ambitious two-year automotive design and engineering program. The program, ULSAB-AVC (Advanced Vehicle Concepts), broadens the ULSAB series of initiatives by going beyond the body-in-white to include closures, suspensions, engine cradle, and all structural and safety-related components. The consortium has commissioned Porsche Engineering Services Inc. (PES, Troy, MI) to undertake the program. PES will integrate automotive-industry feedback and the knowledge it has already acquired in the development of the ULSAB body structure into the new initiative.

Some of the breakthrough technology that the consortium hopes to explore in detail is:

Increased use of hydroforming, particularly in the production of large, thin-wall tube side-roof rails.

  • Further development of galvanized steel sheet for roofs, hoods, decklids, fenders, and other automotive components.

  • Increased use of tailor-welded steel sheet blanks to precisely place various steel grades and thicknesses within a part where their attributes are most needed.

  • Laser welding of automotive components as a subassembly.

In addition to using these technologies to improve the quality of steel automotive parts, the consortium also will investigate how to simplify the task of parts repair.

Aluminum's advances. Not to be outdone, the aluminum industry has its own agenda to further increase the interest of automakers. In a major coup, the 80-mpg PNGV project identified aluminum as one of the most promising technologies for meeting the program's goal of having production-ready prototype sedans by 2004 with a fuel economy of up to three times that of 1994 vehicles without compromising safety, size, utility, or cost.

Aluminum already has made inroads in these areas. For example, according to the latest Drucker Research Co. report, several 1999 model GM vehicles have significantly more aluminum content than the vehicles they replace, ranging from 224 lbs (27% increase) for the Sierra pickup to 485 lbs (20% increase) for the Cadillac Deville. The Ford F-series pickup leads the platform pack with more than 200 million lbs of aluminum used, while the Plymouth Prowler is the single-vehicle content leader at 963 lbs.

However, with steel producers breathing down their necks, the Aluminum Association recently revised its goals in an attempt to keep aluminum at the forefront of future auto designs. A recent publication of the association, "Aluminum Industry Roadmap for the Automotive Market: Enabling Technologies and Challenges for Body Structures and Closures," identifies many of the research needs. Action items include:

Develop processes and technologies to reduce the cost of ingot.

  • Improve understanding of the relationship of aluminum alloy composition and processing and its effect on microstructure and properties.

  • Develop improved casting processes (including continuous casting) to produce low-cost, defect-free sheet.

  • Establish common alloy and testing, i.e., reduce the number of alloy variants and test practices.

  • Develop advanced methods for integrating product design and the material and processing selection.

"The goal of our research is to increase the efficiency with which aluminum is used and to reduce the cost of the processes to convert it from an ingot/sheet/extrusion product into a serviceable part or an integral component of the vehicle," says John A.S. Green, the association's vice president, technology. "Essentially every R&D effort proposed contributes directly or indirectly to lowering the cost of using aluminum in automobiles."

Whatever the outcome of this materials war, one thing is certain: Auto makers and consumers alike are sure to benefit from any new developments that help make cars less costly to produce and more fuel efficient.

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