Last week, the U.S. Court of Appeals for the Federal Circuit denied a petition by ArcelorMittal (NYSE:MT) to rehear its patent infringement lawsuit against AK Steel (NYSE:AKS) regarding aluminized boron steel used primarily for high-strength automotive applications. 

By rejecting the petition, the court affirmed that AK didn't infringe on Arcelor's patent, which allows it to sell its Ultralume aluminized boron steel product. The verdict will eliminate customer concerns over the pending litigation that had convinced the company to hold the product back even though it has had production capabilities for years.

Arcelor had sued AK and two other steel producers, charging they infringed on a U.S. patent for the specialized steel, but a jury in 2011 found the patent was invalid and no infringement had occurred. Arcelor had petitioned the court to rehear the decision but was rebuffed by the appeals court.