A Steckel mill is a type of metalworking tool that is used to turn steel ingots into metal sheets. Also called a reversible finishing mill, a Steckel mill uses a series of rollers to turn raw metal into flattened, usable metal. They are called reversible finishing mills because the rollers on the machine can be set to roll both forward and backward over the raw material. A more modern type of mill, the Steckel mill allows finishing to occur in fewer passes through the machine than in other mill types.
In Steckel and similar mills, rollers are used to flatten out metal stock. The rolling process can be hot or cold, depending on the temperature. It is considered hot rolling when the temperature of the rollers is higher than the recrystallization point of the metal. When the temperature of the rollers is lower than the recrystallization temperature of the metal, it is called cold rolling. The most tonnage each year is produced by hot rolling. A Steckel mill can be used for either hot or cold rolling, though hot is more common.
There are several types of mills that can be used in rolling and finishing metal. A Steckel mill is a type of tandem rolling mill. This means that the mill is composed of a series of different, connected rollers that the metal passes through. Instead of having to pass the metal through one set of rollers several times, the same finish can be achieved with just one pass through a Steckel mill, though multiple passes through the entire mill may still be required.
The design of a Steckel mill includes two coilers instead of the normal single coiler on most rolling mills. The coilers direct the flow of the metal into and out of the machine. At the entrance of the machine, the first coiler pulls the material into the work area. The second coiler is found at the exit and pulls the worked material through and out of the machine. If desired, the coilers can be reversed so that the exit coiler pulls the material back through the rollers, working the metal through the finishing process again.
These mills also feature heated reels, or drums, that the finished product can be rolled onto as it comes out of the machine. The drums not only store the product until the direction of the rolling is reversed, but they also help keep the product consistent and uniform. In this way, the manufacturer can process a larger quantity of material at one time than on some other mills.