Timken Four-Row Cylindrical Roller Bearings RYL for Long Product Mills

Four-row cylindrical roller bearings built for roll necks in long product mills

The Timken RYL four-row cylindrical roller bearing is a roll-neck bearing for long product rolling mills, where bar, rod and section mills change rolls often and cannot afford bearing damage during roll changes. Four-row cylindrical bearings have very high radial load capacity but no thrust capacity, and they are mostly used in roll neck and work roll applications in the metal rolling industry. Timken built the RYL on its earlier RY design, replacing the brass cage with a machined steel cage and adding an inner-ring chamfer to make mounting easier and reduce collision damage between the inner ring and the outer assembly.

The RYL and RXL types have finger-type machined steel cages, case-carburised rings and rollers, a one- or two-piece inner ring, lubrication slots on the outer-ring faces, a modified inner-ring chamfer and reduced roller drop. Precision is P6 for the boundary dimensions and P5 for run-out, which supports the quality of the finished product.

Technical specifications

Part-number listing from the Timken sheet: bore / outside diameter / width in mm, diameter under rollers (DUR) in mm, mass in kg, with the inner ring and outer assembly numbers:

Reading the number and ordering a replacement

A full assembly such as 280RYL1782W33C4 reads: 280 mm bore, RYL design type, series number 1782, W33 modification codes and C4 radial internal clearance. The inner ring is numbered 280ARYSL1782W30B (diameter bore, ARYSL two inner rings, series, modification code) and the outer assembly 308RYSL1782W33, where 308 is the diameter under the rollers. ARVSL is the one-piece inner ring and ARYSL the two-piece. Figure 1, 2 or 3 in the sheet shows the geometry for each size.

Timken prints competitive reference numbers beside each assembly (SKF, FAG, NSK and ARB) so that a mill can match an existing bearing: for example 280RYL1783 is listed against SKF 313822 and FAG 507339, and 200RYL1567 against SKF 313893 and FAG 508726. Check the reference against the data on the bearing in the chock before ordering.

What to confirm before ordering

Confirm the complete designation stamped on the bearing, one- or two-piece inner ring, outer assembly number, clearance class, lubrication method and the roll-change practice at the mill. The sheet does not list load ratings, so ask for the rating tables where life calculations are needed. Other Timken stock is listed under Electric Motors, Pumps and Turbines.

Mounting the RYL assembly on the roll neck

Because the RYL is a separable assembly, the inner ring and the outer assembly are handled as two parts during roll changes. Work in a clean area of the roll shop, keep the outer assembly covered until it is fitted into the chock, and inspect the roll neck and chock bore for burrs, damage and old lubricant before assembly. Fit the inner ring to the roll neck using the method set out in the mill procedure and the Timken mounting instructions, and slide the chock with its outer assembly over the inner ring squarely so that the rollers are not forced against the ring edge. Keep matched components together and record which inner ring and outer assembly were used in each chock.

Lubrication and roll-shop maintenance

Use the lubricant type and quantity specified by the mill or the bearing engineering team, and make sure the lubrication slots in the outer-ring faces are not blocked when the chock is assembled. Each roll change is a chance to inspect the bearing: look for discolouration, smearing, spalling, corrosion or contamination by scale and cooling water, and compare the findings with the previous record for that chock. Bearings that show early damage should be removed from service and assessed before they are refitted, rather than left to fail in the stand.

Record keeping per chock

A simple record of chock number, bearing designation, hours or tonnage rolled, and inspection notes helps the mill see which stands wear bearings fastest and whether changes in lubrication or sealing practice are working.

Operating conditions in GCC long product mills

Bar and rod mills in Oman and the wider Gulf combine hot process conditions with high summer ambient temperatures and, in many locations, fine airborne dust. These conditions put more demand on lubricant life and on the cleanliness of the roll shop. Store spare bearings in their packaging in a dry, covered area away from direct sun and dust, rotate stock so older bearings are used first, and avoid opening packs until the bearing is about to be mounted. In coastal plants with humid air, protect stored bearings and chocks against corrosion between roll changes.

Checks before selecting a replacement

Confirm the bore, outside diameter and width against the table, the inner-ring type, the clearance class and any modification codes, and compare the competitive reference with the number on the bearing currently in service. Where the stamped number on the old bearing is hard to read, measured dimensions and the chock drawing help confirm the correct assembly before the request is sent.

Documents and quotation

The attached Timken sell sheet lists all assemblies, inner rings and outer assemblies with the printed references. Send the designation and quantity when requesting a quotation from Seven Star LLC, an independent supplier in Muscat.