AK Steel Holding Corporation is an American steel company whose predecessor, Armco, was founded in 1899 in Middletown, Ohio, United States. In 2007, the company moved its corporate headquarters from Middletown to West Chester, Ohio.

AK Steel Holding Corporation is an American steel company whose predecessor, Armco, was founded in 1899 in Middletown, Ohio, United States. In 2007, the company moved its corporate headquarters from Middletown to West Chester, Ohio.