Rolls have different classification methods. According to the shape of the roll body, it is divided into cylindrical and non-cylindrical shapes. The former is mainly used for the production of plates, strips, profiles and wires, and the latter is mainly used for pipe production. It is divided into work rolls and backup rolls according to whether they are in contact with the rolling stock. Rolls that are in direct contact with the rolled stock are referred to as work rolls; rolls that are placed on the back or side of the work rolls and that are not in direct contact with the rolled stock are referred to as support rolls for increasing the stiffness and strength of the work rolls. According to the use of the frame, it is divided into a preliminary roll, a rough roll, an intermediate roll and a finish roll. According to the variety of rolled materials, it is divided into strip rolls, rail rolls, wire rolls and pipe rolls. It can also be divided into a hot roll and a cold roll according to the state of the rolled piece at the time of rolling.