Steel Mills
December 8, 2015
ArcelorMittal Patent Declared Invalid in Infringement Suit with AK Steel
Written by Sandy Williams
A Delaware judge invalidated a patent by ArcelorMittal in a ruling favoring AK Steel in a dispute that has been ongoing for almost six years.
The original suit, filed in January 2010 by ArcelorMittal, claimed that AK Steel’s lightweight, high-strength steel Ultralume, used in automotive applications, violated ArcelorMittal’s 2001 patent (patent 6,296,805—referred to as ‘805) for its Usibor steel. In 2011, a jury ruled that the ArcelorMittal patent on the aluminum coated boron steel was invalid. A judge in August 2011 refused an appeal by ArcelorMittal, saying that the process of coating steel with aluminum and heat treating was publically disclosed by a steel expert during a trade conference before the ArcelorMittal patent date.
