A strip mill is a type of steel mill invented in the early 1900s. Strip mills and their new technology produced larger sheets of steel at lower costs, revolutionizing the industry and the future of steel. With increased production at lower costs, steel and tin could be used for many more products.
There are several types of strip mills that have been used throughout the history of steel mills. The earliest type of strip mill was the hot rolling strip mill. Early hot rolling mills could not produce strip that was suitable for tinning, as the gauge of the steel was too thick.
Hot rolling strip mills were followed by cold rolling strip mills. Cold rolling strip mills were first established around 1929 and were able to produce steel at a lower gauge. Along with the technology of cold rolling milling and lower gauge steel, tinning was then made possible. Strip mills are the most common ones in operation today. While most present-day mills were built before 1970, the strip milling process continues to be modernized to meet the current demands and standards of the steel industry.
The first strip mill was built in 1923 in Ashland Kentucky, but the method and process used at a strip mill was first invented by John Butler Tytus, Junior around 1918. Tytus was working for the American Rolling Mill Company (ARMCO) in Ohio at the time. The demand of the automobile and appliance industries was blossoming and created a huge need for steel. Tytus hoped to find a better and more efficient way to produce sheets of steel.
Keeping steel continuously rolling was the key component of the method for steel production invented by Tytus. This process is now known as the continuous hot rolling process. At a pack mill, plates had to be run over the roll and doubled, making the process much slower and more labor intensive. The process used at a strip mill was preferred over the processes of the pack mill because the milling process was continuous. This caused pack mills to eventually become obsolete.
The strip mill had many advantages over the pack mill. While they were quite capital intensive, which could make the startup more difficult, they were much less labor intensive, a change that largely changed the steel milling industry in the 1930s and 40s. The strip mill process also made it possible to use softer steel.