Arcelormittal France v. AK Steel Corp., No. 14-1189 (Fed. Cir. 2015)Annotate this Case
ArcelorMittal alleged infringement of the 805 patent, directed toward a steel sheet with “a very high mechanical resistance” after thermal treatment. The court construed the phrase “very high mechanical resistance” as limited to steel with a tensile strength greater than 1500 MPa. The Federal Circuit affirmed the construction, but remanded on other grounds. While the appeal was pending, ArcelorMittal sought reissue to correct the construction. The application issued as the RE153 patent, adding dependent claims, including: claim 23, which recites “[t]he coated steel sheet of claim 1, wherein said mechanical resistance is in excess of 1000 MPa”; claim 24, which confines claim 1 to the construction affirmed by the Federal Circuit by claiming “[t]he coated steel sheet of claim 1, wherein said mechanical resistance is in excess of 1500 MPa”; and claim 25, which depends on and further limits claim 24. ArcelorMittal amended its complaint. The district court granted summary judgment on remand, finding claims 1 through 23 of the RE153 patent invalid as impermissibly broadened in the reissue proceedings (35 U.S.C. 251.1). The Federal Circuit reversed in part, finding that newly added claims 24 and 25 were not broadened during reissue. The court was bound by its construction of the original claims; the reissue claims broadened that construction.