Latest Advanced High Strength Steel from U. S. Steel Enters Production

United States Steel Corporation (NYSE: X) announced today that its automotive customers are now evaluating and qualifying the company's new hot-dipped galvanized DUAL-TEN 780 product for structural applications. Commercial quantities of DUAL-TEN 780 are now available in a range of thickness from 1.0 mm to 2.0 mm and in widths up to 1370 mm.

One customer, U. S. Steel noted, has already successfully produced parts from trial quantities of 1.0 mm and 1.2 mm dual phase galvannealed sheet having a minimum tensile strength of 780 MPa. The company also provides hot- dipped galvanized DUAL-TEN 600 for the recently launched General Motors 2004 Chevrolet Malibu.

U. S. Steel was the first American steelmaker to develop and produce commercially a family of dual phase steels, trademarked DUAL-TEN. These steels are 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.

John Peters, general manager-automotive at U. S. Steel's Automotive Center in Troy, Michigan, said, "U. S. Steel is pleased to be the first domestic steel producer to have parts successfully stamped from DUAL-TEN 780. This is another example of U. S. Steel working with our customers early in their vehicle development process to bring new steels into commercial application."

Dual phase steels offer an exceptional combination of strength and formability. Their high ductility is due to a microstructure consisting of a fine dispersion of hard martensite particles in a soft ferrite matrix. These grades have a high strain hardening capacity, enhancing strain redistribution and thus providing good formability. Work hardening during forming also increases the yield strength in finished parts to much higher strengths than in the initial blank. The combination of high strength and ductility and the capacity for strain hardening leads to excellent fatigue properties and good energy absorption characteristics, making these steels suitable for structural and reinforcement components. These properties can be enhanced further by marked strain hardening combined with a pronounced bake-hardening effect, offering an excellent potential for weight savings in structural parts.

Recently, U. S. Steel also introduced Hot Rolled 590SF for high strength applications requiring stretch flanging, especially at circular holes. The commercially available steel is being used to replace castings for applications in control arms and suspension members.

SOURCE: United States Steel Corporation

CONTACT: Mike Dixon, +1-412-433-6860, or John Armstrong,
+1-412-433-6792, both of United States Steel Corporation

Web site: http://www.ussteel.com/

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