What Should Be Paid Attention to in Mill Roll Classification and Selection

Roll is the main working part and tool for continuous plastic deformation of metal in the rolling mill. The roll is mainly composed of the roll body, roll neck, and shaft head. The roll body is the middle part of the roll actually involved in rolling metal. It has a smooth cylindrical or grooved surface. The roll neck is installed in the bearing and transmits the rolling force to the frame through the bearing seat and the screw-down device. The shaft head at the driving end is connected with the gear seat through the connecting shaft to transmit the rotating torque of the motor to the roll. The rolls can be arranged in the form of two, three, four, or more rolls in the mill frame.

Roll Classification

There are many classification methods for rollers, mainly including:

(1) According to the product type, there are strip steel roll, section steel roll, wire rod roll, etc;

(2) According to the position of the roll in the rolling mill series, there are opening roll, roughing roll, finishing roll, etc;

(3) According to the roll function, there are scale breaking roll, piercing roll, leveling roll, etc;

(4) According to the roll material, there are steel roll, cast iron roll, cemented carbide roll, ceramic roll, etc;

(5) According to the manufacturing method, there are casting roll, forging roll, surfacing roll, insert roll, etc;

(6) According to the rolled steel status, there are hot rolls and cold rolls.

Various classifications can be combined accordingly to make the roll have a more clear meaning, such as centrifugal casting high chromium cast iron work roll for hot strip steel.

Roll Selection

See the table for commonly used roll materials and applications. The performance and quality of the roll generally depend on its chemical composition and manufacturing method and can be evaluated by its microstructure, physical and mechanical properties, and the residual stress type existing in the roll (see roll inspection). The application effect of roll in a rolling mill not only depends on the roll material and its metallurgical quality, but also on the service conditions, roll design, operation, and maintenance. The roller service conditions of different types of rolling mills are very different. The factors causing the differences are: (1) rolling mill conditions. Such as rolling mill type, rolling mill, and roll design, pass design, water cooling conditions, and bearing types; (2) Rolling conditions such as variety, specification and deformation resistance of rolled products, reduction system, and temperature system, output requirements and operation, etc; (3) Requirements for product quality and surface quality, etc.