In the steel and non-ferrous metal rolling industry, the rolling mill is the core equipment for achieving plastic deformation of materials. Its working environment is extremely harsh, usually accompanied by high temperatures, heavy loads, high speeds, impacts, and water mist dust. Under such harsh working conditions, the performance of bearings is crucial as they support the rolling mill and ensure rolling accuracy. Among them, four-row cylindrical roller bearings and four-row tapered roller bearings have become the preferred roller bearings due to their excellent load-bearing capacity, and are widely used in the roll neck of rolling mills, directly supporting the work roll or support roll.
When the rolling mill is in operation, the rollers need to withstand huge radial forces (used for rolling) and certain axial forces (such as when the plate deviates) from the material being rolled. At the same time, the rolling process may generate vibration and impact, and the ambient temperature is high, accompanied by cooling water and iron oxide scale. This requires bearings to have extremely high radial and axial load-bearing capacity, impact toughness, stable rotational accuracy, and good sealing and lubrication performance.
Four-row cylindrical roller bearings are renowned for their enormous radial load-bearing capacity and high-speed characteristics. It adopts a design with four parallel rollers, which evenly distributes the load and can perfectly cope with the huge radial forces generated during the rolling process. Due to its internal structural characteristics, it usually cannot withstand axial forces, so it needs to be paired with a separate thrust bearing (such as a double row angular contact ball bearing) for use.
Main application: It is mainly used in situations where rolling force is extremely high and radial stiffness is required, such as on the support rollers of various plate mills and strip mills. Here, the main task of the bearing is to stably support the rolling mill and withstand almost all radial loads, while axial positioning is carried out by the matching thrust bearing.
The design of four-row tapered roller bearings is more comprehensive. It not only withstands extremely high radial loads through four rows of tapered rollers, but also relies on its tapered structure to withstand bidirectional axial loads. This "two in one" design simplifies the structure of the bearing seat, making it more integrated and relatively easy to adjust and maintain.
Main application: Widely used in situations where heavy radial forces and large axial forces are simultaneously borne, commonly found in various types of work rolls, especially in hot rolling mills. The work roll requires frequent forward and reverse rotation and can withstand uncertain axial impacts. Four row tapered roller bearings can simultaneously provide radial support and axial positioning, ensuring the stability of the roll during high-speed rolling and preventing strip deviation.
In summary, four-row cylindrical roller bearings and four-row tapered roller bearings are the core components that ensure the efficient and precise operation of modern rolling mills. The choice of bearing depends on the specific structure of the rolling mill, rolling process (hot or cold rolling), and stress characteristics. Correctly selecting and maintaining these 'strong arms' has immeasurable value in improving the quality of rolled products, reducing equipment failure rates, and increasing production efficiency.
