U. S. Steel's New Family of Dual-Ten™ Steels Will Help Make Automobiles Lighter, Safer and More Fuel Efficient
United States Steel LLC (NYSE: X) has become the first American steelmaker to develop and produce commercially a family of dual phase steels. Marketed under the trademark DUAL-TEN™, 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™ 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™ 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™ 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™ 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™ 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™ steels provide a remarkable combination of formability, strength, ductility, durability, strain-rate sensitivity and strain hardening characteristics."
"DUAL-TEN™ 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."
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SOURCE: United States Steel LLC
Contact: Tom Ferrall, +1-412-433-6899, or John Armstrong,
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