Four Row Cylindrical Roller Bearing Benefits for Rolling Mills
Extreme demands are placed on bearings in rolling mills. Heavy radial loads, high speeds, and tight strip precision all converge at the roll neck, and the bearing used here will affect both product quality and maintenance costs. This is the reason why the four row cylindrical roller bearing has become one of the major bearing types in contemporary mills. Since 1998, CHG Bearing (Luoyang Huigong Bearing Technology Co., Ltd.) has been designing and manufacturing rolling mill bearings. In this essay, we will cover the advantages, construction, materials, and practical usefulness of these bearings, so you may specify them with confidence.
Why Is a Four Row Cylindrical Roller Bearing So Well Suited to Rolling Mills?
Strong Radial Load Capacity
A rolling mill roll pushes steel with a great force. The majority of the force is in the radial direction. A cylindrical roller bearing with four rows puts four rows of rollers into one assembly, and the line contact between rollers and raceways distributes the load over a large region. This provides the bearing with a very high radial load capacity in a constrained area, allowing mill designers to keep roll chocks small, but still reliably handle enormous rolling forces.
High Stiffness for Accurate Strip Thickness
Strip thickness is a function of how little the roll deflects under stress. The four-row cylindrical roller bearing is characterized by its high rigidity, which ensures rigid support of the roll neck and little movement during rolling. This solid foundation enables mills to maintain tight thickness tolerances and exceptional flatness. For operations manufacturing cold or hot sheet, this rigidity immediately translates into improved product uniformity and fewer rejected coils.
Compact Structure Saves Installation Space
Roll chocks are tight, and every millimeter matters. The compact design of a four-row cylindrical roller bearing packed in a tiny envelope gives great capacity and allows engineers to include lubrication channels and sealing solutions. This space-saving efficiency makes the bearing a feasible solution for both new mill designs and for upgrading older stands with set chock dimensions.
Which Four Row Cylindrical Roller Bearing Series and Sizes Are Available?
FC, FCD, and FCDP Series Overview
Three well-recognized series are available to mill designers: the FC, FCD, and FCDP. Every four-row cylindrical roller bearing series follows the same general principle, but varies in the internal design and mounting details. This enables the engineer to adapt the bearing to the roll neck and chock arrangement. With numerous series to select from, we have a suitable solution for most mill stands, from smaller bar mills to hefty cogging mills.
| Series | Bearing Type | Typical Use |
|---|---|---|
| FC | Four-row cylindrical roller bearing | General mill roll necks |
| FCD | Four-row cylindrical roller bearing | High-load roll stands |
| FCDP | Four-row cylindrical roller bearing | Precision, high-speed mills |
Wide Size Range from 90 to 1400 mm
Mills range in size from tiny wire mills to massive sheet mills. Each four row cylindrical roller bearing is available with an inner diameter from 90 mm to 1400 mm. Designers are free to choose the size that matches their roll neck. The breadth also allows businesses to standardize on one supplier for numerous mill lines, simplifying buying and spare parts planning.
Matching Size to Mill Duty
The proper size is a compromise between load, speed, and accessible space. Engineers normally begin by considering the roll neck diameter and the rolling force and then verify that the four-row cylindrical roller bearing is adequately rated for capacity and life for the specified task. Since they share mill data with the manufacturer, the technical staff may prescribe a size and series that will provide reliable service over many rolling sessions.
What Materials and Cage Designs Support Long Service Life?
High-Quality Bearing Steels
Material quality is the basis of bearing life. A four-row cylindrical roller bearing for rolling mills is often constructed from GCr15, GCr15SiMn, or G20Cr2Ni4A steel. GCr15 and GCr15SiMn are typical through-hardening bearing steels, whereas G20Cr2Ni4A is a carburizing steel that has a hard surface and a tough core. The choice of the proper grade allows the bearing to endure stress loads and lengthy working hours.
| Item | Options |
|---|---|
| Steel grades | GCr15, GCr15SiMn, G20Cr2Ni4A |
| Cage types | Brass solid cage, pin-type cage |
| Size range | Inner diameter 90–1400 mm |
Brass Solid Cages and Pin-Type Cages
The cage maintains the rollers uniformly spaced and directed as it turns. Four row cylindrical roller bearings are generally fitted with brass solid cages or pin-type cages. Both types of cages are noted for strength and steady guiding at high speed. Brass cages are resistant to vibration and heavy-duty use, while pin-type cages ensure solid roller retention. Proper cage selection allows the bearing to roll smoothly under the rigorous circumstances of a mill.
Manufacturing Precision and Inspection
Long life also relies on the precision of manufacture. CHG Bearing has more than 150 pieces of major production equipment and more than 70 sets of testing equipment, including CMM, metallographic microscope, roundness meter, friction torque tester, UT, MT, and ET. This inspection capability ensures consistent quality in every four-row cylindrical roller bearing, providing mill operators assurance that dimensions, material structure, and operating performance satisfy exacting criteria.
How Does the Design Simplify Mounting and Maintenance in Rolling Mills?
Inner Rings Without Ribs
The four-row cylindrical roller bearing has the important property that the inner rings are ribless. This permits the inner ring and outer ring assembly, with the whole set of rollers and cage, to be handled individually. Roll changes are easier and take a little time to prepare since components may be moved into position with less effort and less chance of harm.
Convenient Cleaning and Inspection
The separability of the pieces makes a four-row cylindrical roller bearing easy to clean and examine. Maintenance personnel may see the raceways, rollers, and cage, note their condition, and determine if the bearing is suitable for another campaign. This quick access allows plants to plan maintenance routines and make educated choices on bearing reuse and replacement.
Suitable Applications Across Mill Types
Four-row cylindrical roller bearings are highly appreciated when high speed and accuracy are needed. Typical examples include wire mills, bar and form mills, cold and hot sheet mills, and cogging mills. In each instance, the four-row cylindrical roller bearing supports large radial loads in a compact, rigid configuration. It is intended to take radial load rather than axial load; hence, mills generally use it with a separate bearing for thrust.
Conclusion
The four row cylindrical roller bearing is a favored option for rolling mills because of its high radial capacity, rigidity, compact size, and ease of installation. FC, FCD, and FCDP series from 90 to 1400 mm diameter, with excellent steels and strong cages, provide accurate rolling and long service life. CHG Bearing is there for you with design experience, innovative equipment, and rigorous inspection on every order. Tell us about your mill needs now, and our specialists can assist you in picking the proper bearing for more production.
FAQ
1. What is a four-row cylindrical roller bearing used for?
It supports roll necks in rolling mills such as wire, bar, shape, sheet, and cogging mills.
2. Which series does CHG Bearing offer?
The FC, FCD, and FCDP series are available.
3. What sizes are available?
Inner diameters range from 90 mm to 1400 mm.
4. Can the bearing carry axial load?
No, it carries high radial loads, so a separate bearing usually handles thrust.
5. Which materials and cages are used?
Steels include GCr15, GCr15SiMn, and G20Cr2Ni4A, with brass solid or pin-type cages.
Ready to Upgrade Your Mill with a Four Row Cylindrical Roller Bearing? Contact CHG Bearing Today
Every rolling mill has its own demands, and the right four row cylindrical roller bearing begins with a clear conversation. Send your drawings, roll neck sizes, and operating conditions to sale@chg-bearing.com, and the CHG Bearing team will reply with professional advice and a tailored quotation. With experienced engineers, advanced testing equipment, and a focus on long-life mill bearings, we are ready to help your production run longer, smoother, and more efficiently.
References
1. Harris, T. A., & Kotzalas, M. N. Rolling Bearing Analysis: Essential Concepts of Bearing Technology. CRC Press.
2. ISO 281:2007. Rolling Bearings – Dynamic Load Ratings and Rating Life. International Organization for Standardization.
3. ISO 15:2017. Rolling Bearings – Radial Bearings – Boundary Dimensions, General Plan. International Organization for Standardization.
4. Roberts, W. L. Cold Rolling of Steel. Marcel Dekker.
5. Roberts, W. L. Hot Rolling of Steel. Marcel Dekker.
6. Ginzburg, V. B. Steel-Rolling Technology: Theory and Practice. Marcel Dekker.
