AK Steel Prevails on Key Claim in Patent Lawsuit

               AK Steel Prevails on Key Claim in Patent Lawsuit

PR Newswire

WEST CHESTER, Ohio, Dec. 3, 2012

WEST CHESTER, Ohio, Dec.3, 2012 /PRNewswire/ --AK Steel Corporation
(NYSE:AKS) said today that the United States Court of Appeals for the Federal
Circuit has issued a decision confirming that AK Steel has prevailed on a key
claim in a patent infringement lawsuit brought against the company by two
French units of ArcelorMittal. The suit, which was tried in the U.S. District
Court in Delaware, alleged that AK Steel and two other steel producers have
infringed upon a U.S. patent for aluminum-coated, boron-bearing carbon steel,
used primarily for high-strength automotive applications.

On January 14, 2011, a jury found that AK Steel did not infringethe
ArcelorMittal patent and that the patent was invalid. In its decision, the
Court of Appeals affirmed a basis for the jury finding of no infringement, but
reversed certain findings related to the validity of the patent and remanded
the case for further proceedings. Those proceedings include a new trial with
respect to AK Steel's claims that the patent is also invalid. 

AK Steel said that, regardless of the outcome of the new trial on the validity
of the patent, the Court of Appeals decision will allow the company to
continue to offer the product for sale to customers in the United States.

AK Steel
AK Steel produces flat-rolled carbon, stainless and electrical steels,
primarily for automotive, infrastructure and manufacturing, construction and
electrical power generation and distribution markets. The company employs
about 6,200 men and women in Middletown, Mansfield, Coshocton and Zanesville,
Ohio; Butler, Pennsylvania; Ashland, Kentucky; Rockport, Indiana; and its
corporate headquarters in West Chester, Ohio. Additional information about AK
Steel is available on the company's web site at www.aksteel.com.

AK Tube LLC, a wholly-owned subsidiary of AK Steel, employs about 300 men and
women in plants in Walbridge, Ohio and Columbus, Indiana. AK Tube produces
carbon and stainless electric resistance welded (ERW) tubular steel products
for truck, automotive and other markets. Additional information about AK Tube
LLC is available on its web site at www.aktube.com.

AK Coal Resources, Inc., another wholly-owned subsidiary of AK Steel, controls
and is developing metallurgical coal reserves in Somerset County,
Pennsylvania. AK Steel also owns 49.9% of Magnetation LLC, a joint venture
headquartered in Grand Rapids, Minnesota, which produces iron ore concentrate
from previously mined ore reserves.

SOURCE AK Steel Corporation

Website: http://www.aksteel.com
Contact: Media, Barry L. Racey, Director, Government and Public Relations,
+1-513-425-2749, or Investors, Albert E. Ferrara, Jr., Senior Vice President,
Corporate Strategy and Investor Relations, +1-513-425-2888