An ArcelorMittal patent on lightweight steel that was rescued by a U.S. appeals court in May has been invalidated again on remand by a Delaware federal judge, who said the company has only itself to blame.

U.S. District Judge Sue Robinson ruled in favor of defendant AK Steel and its attorneys at Covington & Burling, saying that ArcelorMittal's reissued patent was obvious in light of previous inventions. She said if the company had continued to litigate against AK Steel using its original patent, instead of the reissued one, it might be in a better position today.

reuters.com