From Ohio History Central
Postcard of Armco Company ball park. Courtesy of the Middletown Public Library.
John Butler Tytus, Jr., invented a process to manufacture continuously rolling sheets of steel. This process, known as the continuous hot strip mill, reduced the manufacturing time and cost of sheet steel.
In 1904, Tytus found employment at the American Rolling Mill Company (ARMCO) in Middletown, Ohio. In 1918, while working at ARMCO, Tytus developed his process for manufacturing sheet steel. Sheet steel was in great demand due to the blossoming automobile industry. Automobile manufacturers used sheet steel to construct car bodies. Manufacturers also used sheet steel for many types of appliances.