Depending on the thickness of the mold or slab the steel may need to go through a roughing mill. Most mini mills start with a two to three inch slab and can take the steel directly into the hot-finishing mill. Integrated mills, which start with a much thicker eight to ten inch slab use “roughers” ahead of the finish mills.
Here, each slab travels through up to six rolling stands, which reduce the thickness of the slab from roughly two inches to gauges from 0.055” to 0.94”.
When the steel has been reduced to the proper gauge it passes over a “run out” table where it is sprayed with water from the top and bottom to the desired coiling temperature. The steel chemistry and processing temperature determine the mechanical properties.
Coils leaving the hot mill are called hot bands. Hot bands can be sold as is, skin passed or moved onto the cold mill for further processing.
The largest amount of hot-band steel is used in the pipe and tubing industry.