A rolling mill, also known as a reduction mill or mill, has a common construction independent of the specific type of rolling being performed:
- Backup rolls - are intended to provide rigid support required by the working rolls to prevent bending under the rolling load
- Rolling balance system - to ensure that the upper work and back up rolls are maintain in proper position relative to lower rolls
- Roll changing devices - use of an overhead crane and a unit designed to attach to the neck of the roll to be removed from or inserted into the mill.
- Mill protection devices - to ensure that forces applied to the backup roll chocks are not of such a magnitude to fracture the roll necks or damage the mill housing
- Roll cooling and lubrication systems
- Pinions - gears to divide power between the two spindles, rotating them at the same speed but in different directions
- Gearing - to establish desired rolling speed
- Drive motors - rolling narrow foil product to thousands of horsepower
- Electrical controls - constant and variable voltages applied to the motors
- Coilers and uncoilers - to unroll and roll up coils of metal
Slabs are the feed material for hot strip mills or plate mills and blooms are rolled to billets in a billet mill or large sections in a structural mill. The output from a strip mill is coiled and, subsequently, used as the feed for a cold rolling mill or used directly by fabricators.