Arcelormittal Atlantique v. AK Steel Corp., No. 17-1637 (Fed. Cir. 2018)Annotate this Case
Plaintiff’s asserted RE940 patent, a reissue of its 805 patent, relates to boron steel sheets with an aluminum-based coating that, when hot-stamped, become highly mechanically resistant. In 2010, plaintiff sued AK Steel for infringement. The primary issue was whether steel sheets produced by AK met the mechanical resistance limitation of the 805 patent after thermal treatment. While the 2010 case was on remand, Plaintiff filed the complaint related to this appeal, asserting the RE940 patent. According to AK, the accused products in this case—steel sheets marketed and sold under the trade name ULTRALUME—are the same as the AXN steel sheets in the 2010 case. The district court granted AK summary judgment, citing collateral estoppel. The Federal Circuit vacated and remanded. Evidence indicates a material difference in the accused products, so collateral estoppel does not apply. Differences with respect to the claimed limitations constitute changes in controlling facts. Discovery is necessary to determine whether and to what extent AK supplied auto manufacturers with steel sheets with ultimate tensile strength in excess of 1,500 megapascals after thermal treatment, its knowledge and intent in doing so, and the relationships between AK, the hot-stampers, and the auto manufacturers during the relevant timeframe.