AK Steel Corporation said 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 14 January 2011, a jury found that AK Steel did not infringe the 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.