AK Steel spokesman Alan McCoy said the settlement is fair for both sides.
The settlement was modeled on a 2006 lawsuit settled in 2008 between AK Steel and about 4,900 retirees from Middletown Works.
That settlement established a $663 million trust fund, managed by retirees that will continue to pay for their benefits until they die.
Butler Works retirees filed the suit June 2009. The original dispute was that AK Steel was taking away certain benefits effective Jan. 1, 2007, and on Jan. 1 2010, they were going to start charging premiums for the first time, Coleman said.