AISI Issues Steel Bumper Design Manual Containing New Steels and New Manufacturing Technology

Detroit, MI - The Bumper Project Group of American Iron and Steel Institute (AISI) has just issued a comprehensive revision to its 152-page manual, Steel Bumper Systems for Passenger Cars and Light Trucks. The manual is available either on CD-ROM or online atwww.autosteel.org.

This is the second revision of the Bumper Manual that was created in 1998, and according to the senior director of AISI's automotive applications, Ron Krupitzer, "We are living up to our promise of bringing state-of-the-art information to bumper manufacturers and the OEMs as fast as it becomes available to us.

He continued, "Bumper systems have changed drastically over the last 20 to 30 years, and they continue to change as automakers adjust to new regulations, strive to improve safety, make vehicles more fuel efficient, and reduce manufacturing costs. Both the steel and automotive industries, working together on project teams like this, are developing new ways to use the advanced high-strength and ultra-high-strength steels available today with superior strength and formability characteristics."

Several tables in the manual provide property values for steels considered for use in bumper systems. These materials range in yield strength from 35 ksi up to and exceeding 200 ksi.

In addition to the precise tabular information on materials, the manual presents design and manufacturing information based on practical experience. In a large, well-illustrated section, data are presented as guidelines or rules of thumb, covering such issues as springback, part design, die construction, blanks, forming and trimming. This section is presented to help address formability and springback issues associated with the roll forming and stamping of high-strength and ultra high-strength steels.

"We have also examined and included in the manual information on advanced manufacturing technologies such as hydroforming, tailored blanks, laser welding, and improved roll-forming. These processes contribute to stronger bumpers at lower cost," said Krupitzer.

There is an extensive section on welding which covers a dozen different welding practices including resistance welding, laser welding, and upset or friction welding. The section includes a table prepared at Ohio State University that ranks the welding processes by the type of bumper material being welded.

There is also a section that gives examples of leading edge bumper beams, which clearly illustrates that steel readily meets the challenges faced by bumper designers in terms of styling, weight, cost and structural integrity. Often designers face a particular problem with one of these criteria. The examples indicate innovative methods that have been used to overcome a variety of design obstacles.

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 Corporation, Ford Motor Company and General Motors Corporation 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 www.autosteel.org.

American Iron and Steel Institute/
Automotive Applications Committee:
Dofasco Inc.
Ispat Inland Inc.
Nucor Corporation
Severstal North America Inc.
United States Steel Corporation