As a typical rolling mill roller bearing, four-row cylindrical roller bearings, ferrules and rolling element components can be easily separated from each other and parts can be interchanged; its installation, disassembly and cleaning are very convenient, with high precision, heavy load, high impact, high speed and other characteristics; its actual life, use and maintenance conditions are related：

There are three main types of four-row cylindrical roller bearings according to the structure type: FC type, FCD type, FCDP type.

FC type is a separable bearing, mainly small bearings. The overall inner ring can be separated from the complete set of bearings. The complete set of bearings consists of two outer ring assemblies and one inner ring. It must be suitable for high-speed (35m/S) rotation. It is mainly used for cold rolling four-roll, six-roll, and twelve-roll rolling mill working roller parts.

FCD type is a separable bearing, mainly medium and large bearings. The complete set of bearings consists of two outer ring assemblies and two inner rings. It is not only suitable for high speed (35m/S) but also can withstand heavy loads at the same time. It is used in profile finishing mills and high-speed wire rough rolling, medium rolling, and pre-finishing parts, including the support rollers, intermediate rollers, and working rollers of cold-rolled non-ferrous and ferrous metal rolling mills below 950.

FCDP type is mainly based on extra-large bearings, which can provide the largest radial carrying capacity and have a low coefficient of friction.Therefore, it is suitable for rolling mill diameters with high speed, heavy load and harsh working environment.

When choosing bearings for rolling mills, these factors such as radial clearance, bearing fit, and limit speed are mainly considered.

Radial clearance is divided into theoretical clearance S0 and working clearance S, which are related to the fatigue life of the bearing. When working conditions require heavy loads and high precision, the radial clearance of the bearing is generally required to be as small as possible; while high-speed, impact-resistant and other working conditions require the bearing to be adapted to a larger clearance.