Innovative Use For Hydroformed Thin-Wall Tubing
9 June 1999
American Iron and Steel Institute Reports on Innovative Use For Hydroformed Thin-Wall Tubing
ULSAB application provides vital structural performance
for crash energy management
DETROIT, June 7 -- Among the many innovations in the
UltraLight Steel Auto Body (ULSAB), the large, thin-wall hydroformed tube side
roof rails are the most interesting. In providing an essential load path for
structural performance and crash energy management, they take advantage of
hydroformed tubing's high dimensional stability and increased effective yield
strength and reflect the technology's growing promise.
Attendees of the Fourth Annual Automotive Tube Conference held April 26-
27, 1999, learned about this and other features of the ULSAB side roof rail
from Ron Miner, senior director, product development at LTV Steel Company.
Miner is a member of the Weight Reduction Task Force of the Automotive
Applications Committee, American Iron and Steel Institute. His paper, ULSAB
Stretches the Limits of Hydroformed Tube Technology, was one of several that
showed why hydroformed tubing is rapidly gaining wider use in a variety of
automotive applications. Key to the ULSAB hydroformed tubes is the
pressurized hydraulic forming process that enables production of complex
shapes in tubular components.
In describing the ULSAB hydroformed tube side roof rail, Miner emphasized
the importance of the essential load path and its critical role in improving
structural performance and crash energy management. At impact, crash energy
is dissipated from the top of the "A" pillar, along the roof, into the "B" and
"C" pillars and down into the rear of the structure through the spring seat
and into the ground.
The raw material for the side roof rail is a welded, high strength steel
tube that is 1 mm thick and has an outside diameter of 96 mm. This is a very
large thin-walled part, considering the rail's structural role. The yield
strength is 280 MPa while the roof is laser-welded to the finished tubes.
Miner also detailed how the ULSAB hydroformed roof rail reduces the total
number of parts and maximizes section size, allowing for mass and cost
savings.
Completed in 1998, ULSAB showed the potential of advanced steels and
innovative design to contribute to lighter weight vehicles. ULSAB was up to
36 percent lighter than a benchmark group of North American mid-size sedans.
Miner's paper is available for viewing and downloading at
http://www.autosteel.org.
American Iron and Steel Institute (AISI) is a non-profit association of
North American companies engaged in the iron and steel industry. The
Institute comprises 48 member companies, including integrated and electric
furnace steelmakers, and 175 associate and affiliate members who are suppliers
to or customers of the steel industry. For a broader look at steel and its
applications, the Institute has its own website at http://www.steel.org.
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
significant 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.
This release and other steel-related information are available for viewing
and downloading at American Iron and Steel Institute/Automotive Applications
Committee's website at http://www.autosteel.org.
Automotive Applications Committee member companies:
AK Steel Corporation
Acme Steel Company
Bethlehem Steel Corporation
Dofasco Inc.
Ispat Inland Inc.
LTV Steel Company
National Steel Corporation
Rouge Steel Company
Stelco Inc.
US Steel Group, a unit of USX Corporation
WCI Steel, Inc.
Weirton Steel Corporation