C31-600-KMB bearing: complete specifications & equivalents
The C31-600-KMB is a ISO 15 radial bearing sized 600 x 980 x 300 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 600 mm |
| Outer diameter D | 980 mm |
| Width B | 300 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 10200 kN |
| Basic static load rating C0 | 18000 kN |
| Fatigue load limit Pu | 1140 kN |
| Reference speed (thermal) | 430 rpm |
| Limiting speed (mechanical) | 600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 929000 g |
| Manufacturer designation | C 31/600 KMB |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & C3100-series range
| Bore d | 23.622 in |
|---|---|
| Outer diameter D | 38.583 in |
| Width B | 11.811 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 190 mm |
| Smallest bore in C3100-series | 100 mm |
| Largest outer diameter in C3100-series | 1580 mm |
| Width range across C3100-series | 52–462 mm |
| Bore position in C3100-series (smallest first) | 23 of 28 |
| Bore above smallest C3100-series size | 500 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C31-600-MB | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 600×980×300 mm ISO 15 envelope and equivalent catalogue C/C0; C 31/600 MB is the cylindrical-bore MB inner-ring-guided brass-caged execution of this size — boundary dimensions interchangeable, only mounting and cage execution differ. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the C31-600-KMB model number is decoded
In SKF catalogue PUB BU/P1 17000, C 31/600 KMB denotes a toroidal roller bearing whose 300 mm long rollers crown at both ends: the contact accepts angular misalignment while the ring positions float, which is why CARB bearings are specified at the free shaft end. In C 31/600 KMB the 31 dimension series fixes the 980 mm OD and 300 mm width around the 600 mm bore (the bore is written directly after the slash (no bore code)); the suffix KMB then selects the tapered 1:12 bore for adapter (H) sleeve mounting, machined inner-ring-guided brass cage (MB). The open execution relies on the housing seals and lubrication system, fed through groove/hole features on the large sizes. Explorer-class heat treatment and the crowned roller profile keep edge stress down when the 600 mm shaft deflects; the 430 r/min reference and 600 r/min limiting speed are both catalogue values. The 929000 g mass over the 600×980×300 mm envelope yields about 17.00 kN dynamic per millimetre of bore — the long toroidal rollers give this family its radial capacity density. After fitting, confirm the inner ring can be pushed axially by hand through the catalogue displacement range; a ring that will not slide means the position is locked and will preload in service.
Typical equipment & failure modes
Common applications
- winder and reel drums in paper and steel strip plants
- paper machine drying cylinders and calender rolls with long, thermally expanding shafts
- continuous-caster guide rolls and slab-caster segments under heat growth
- vibrating screen exciters fitted with the VE240 tolerance execution
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after sustained overload
- thermal preloading when a shaft is located at both ends and growth has nowhere to go
- brass cage pocket wear under marginal lubrication in the large-bore M/MB executions
- hard-particle indentation where oil or grease filtration is inadequate
- grease churning and overheating when a high-speed thrust position is over-packed
Selection pitfalls — read before you substitute
- At 600 mm bore the 929 kg mass and 300 mm width make seating geometry dominant: sphered-washer seats and oil flow must be verified in place, not just on the drawing.
- Do not block the axial displacement in the drawing: housing covers, labyrinth rings and snap rings must leave the catalogue float (s) free, or the bearing silently becomes a poorly located fixed bearing.
- Envelope-identical spherical roller bearings (same ISO 15 d×D×B) are not drop-in equivalents — they locate the shaft axially, while C 31/600 KMB must float; the two are designed to be used as a pair.
- Never use C 31/600 KMB as the locating bearing: it carries no axial load by design — the arrangement needs a separate locating spherical, tapered or angular bearing facing the thrust.
- Tapered-bore K executions mount on adapter sleeves (1:12) and K30 on withdrawal sleeves (1:30) — the 600 mm bore changes the sleeve family, and the drive-up procedure differs accordingly.
- The 10200/18000 kN ratings and 929000 g mass are SKF catalogue values transcribed from ch. 10.1 of PUB BU/P1 17000 (PDF table page 866); mounting data — axial displacement (s) and seating details — appears in the running text because the structured record carries the boundary envelope only.
Frequently asked questions
How is C 31/600 KMB mounted?
The tapered 1:12 bore mounts on an adapter (H) sleeve with a defined drive-up; heat the bearing to max 120 °C when fitting, support full ring faces, and verify axial float afterwards.
What are the dimensions and ratings of the C 31/600 KMB?
A C 31/600 KMB measures 600 mm bore × 980 mm outside diameter × 300 mm width (23.622 × 38.583 × 11.811 in). From SKF catalogue PUB BU/P1 17000: dynamic C 10200 kN, static C0 18000 kN, fatigue limit Pu 1140 kN, reference speed 430 r/min, limiting speed 600 r/min, mass about 929000 g.
Can a CARB bearing like C 31/600 KMB locate the shaft axially?
No — that is the defining feature. C 31/600 KMB deliberately allows the inner ring to float axially inside the outer ring while the toroidal rollers self-align. It must be paired with a separate locating bearing (spherical, tapered or angular contact) that takes 100 % of the thrust.
How is the C 31/600 KMB designation read?
C = CARB toroidal family; 31 = dimension series; 600 mm (slash-size) = 600 mm bore (the bore is written directly after the slash (no bore code)); suffix KMB selects tapered 1:12 bore for adapter (H) sleeve mounting, machined inner-ring-guided brass cage (MB). K is a 1:12 tapered bore for an adapter sleeve, K30 a 1:30 bore for a withdrawal sleeve.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings on 2026-09-27. Read our editorial & correction policy.