U. S. Steel's New Family of Dual-Ten(TM) Steels Will Help Make Automobiles Lighter, Safer and More Fuel Efficient

    TROY, Mich., Aug. 27 United States Steel LLC has
become the first American steelmaker to develop and produce commercially a
family of dual phase steels.  Marketed under the trademark DUAL-TEN(TM), the
new steels have been engineered to meet the demands of automakers for high-
strength, light-weighting materials with improved formability that will help
them reduce vehicle weight and cost while improving crash safety performance.
    U. S. Steel's DUAL-TEN590 steel is currently in use by major automobile
manufacturers in large production volume automobiles, and other grades are
being qualified and implemented in the design of future vehicles.
    Traditional high-strength low alloy (HSLA) steels depend on alloying for
their strength.  This strength, however, comes at a cost to formability and
severely restricts the flexibility of automotive designers to create the
complex automotive components required for efficient lightweight designs.
    Unlike HSLA steels, DUAL-TEN(TM) steels derive their strength from unique
combinations of two crystalline structures, ferrite and martensite, and have
demonstrated advantages over HSLA steels in formability and structural
performance.
    At its automotive center in Troy, Mich., U. S. Steel is demonstrating the
advantages of DUAL-TEN(TM) steels through testing and computer simulation.
    In a comparison with HSLA50, conventional steel with similar yield
strength, DUAL-TEN590 steel demonstrates improved performance in deep draw and
stretch forming stamping operations.  Its superior formability gives
automobile designers greater design flexibility to optimize component shape to
carry loads more efficiently throughout an automobile's structure.
    Studies of the fatigue performance of DUAL-TEN590 steel are currently
under way, however, it is predicted to have a 35 percent advantage over
HSLA50.  The inherent strength of DUAL-TEN(TM) steels is enhanced through
rapid work hardening during the stamping process, and again during the
painting process when the steel becomes bake hardened.  These processes can
increase steel strength as much as 80 percent over the virgin sheet.
    U. S. Steel's DUAL-TEN(TM) steels offer better crash performance over
conventional steel due, in part, to the added strength, but also because of
its strain rate sensitivity, which means the faster the steel is crushed, the
more energy it can absorb.  In 30 mph drop tests, DUAL-TEN590 steel has been
shown to absorb 20 percent more energy than HSLA50.  This means that an
automotive crash component made of DUAL-TEN(TM) steel will perform the same
function using less steel.
    "The demands on the automobile industry to continually improve vehicle
safety and fuel economy while reducing cost will be achieved by innovative
design, advanced material processing and advanced materials," said John
Peters, general manager of automotive for U. S. Steel.  "To help the auto
industry meet these demands, U. S. Steel's DUAL-TEN(TM) steels provide a
remarkable combination of formability, strength, ductility, durability,
strain-rate sensitivity and strain hardening characteristics."
    "DUAL-TEN(TM) steels can provide significant weight reduction with
equivalent or improved strength, durability, and crash performance," said Mike
Juddo, director of product technology at U. S. Steel's automotive center.
"These advanced automotive materials will play a dominant role in the next
decade of vehicle design, to meet the needs of our customers to improve fuel
economy and safety while reducing costs."

    (For more information on U. S. Steel, visit their Website at http://www.usx.com
or http://www.ussteel.com.)

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