231-530BK bearing: complete specifications & equivalents
The 231-530BK is a ISO 15 radial bearing sized 530 x 870 x 272 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 530 mm |
| Outer diameter D | 870 mm |
| Width B | 272 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 7800 kN |
| Basic static load rating C0 | 14200 kN |
| Fatigue load limit Pu | 920 kN |
| Limiting speed (mechanical) | 310 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 633000 g |
| Manufacturer designation | NTN 231/530BK |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & 23100-series range
| Bore d | 20.866 in |
|---|---|
| Outer diameter D | 34.252 in |
| Width B | 10.709 in |
| ISO bore code | 31 |
| Radial section height (D−d)/2 | 170 mm |
| Smallest bore in 23100-series | 100 mm |
| Largest outer diameter in 23100-series | 1420 mm |
| Width range across 23100-series | 52–412 mm |
| Bore position in 23100-series (smallest first) | 27 of 36 |
| Bore above smallest 23100-series size | 430 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 231-530B | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23100-series envelope, cage and ratings; this is the tapered-bore execution (K, 1:12) of the cylindrical-bore 231-530B — mounting (adapter/withdrawal sleeve or tapered seat, drive-up) differs. Verify shaft arrangement. |
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 231-530BK model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 231/530BK denotes the 530 mm bore spherical roller bearing (7800 kN C / 14200 kN C0) in the 23100 series, the self-aligning choice for heavy combined load. Reading the full code: the number gives the 530×870 mm envelope, — names the cage/capacity execution, K marks the 1:12 tapered bore for adapter/withdrawal-sleeve mounting, and plain outer ring (no D1/W33 groove) completes the order number. The sphered outer raceway lets the inner-ring assembly pivot, accommodating shaft deflection and housing misalignment (around 1–2° for this class; use the 2203E value for the exact series) without edge loading the rollers. Catalogue mass 633000 g (633.00 kg) for the 530×870×272 mm execution includes the basic cage and both roller rows; shaft and housing shoulders must support that ring squarely. On vibrating-duty shafts verify the radial clearance class and cage choice at order time; the open 231/530BK leaves sealing and the C3/C4 clearance decision to the application drawing.
Typical equipment & failure modes
Common applications
- mining shovel and dragline swing shafts
- cement-rotary-kiln support and trunnion rolls
- large SAG/ball-mill trunnion and pinion shafts
- heavy vibrating screens and grizzly feeders
Known failure patterns
- lubricant starvation at the centre rib area when the D1/W33 groove is not connected to a relubrication supply
- machined EM cage wear from inadequate oil film at the cage-guiding surfaces
- roller-end smearing during skidding starts under light load and high viscosity grease
- rolling-contact fatigue after the catalogue L10 life at the actual load
- rolling-contact fatigue after the catalogue L10 life at the actual load
Selection pitfalls — read before you substitute
- At 530 mm bore 231/530BK is normally mounted on adapter/withdrawal sleeves with hydraulic assistance; follow the NTN drive-up angle or oil-injection procedure — manual nut tightening cannot set the multi-tonne seating correctly.
- Never substitute 231/530BK by envelope alone: the 14200 kN C0 and 920 kN Pu are specific to the NTN basic execution, and vibrating duty depends heavily on cage identity.
- Never substitute 231/530BK by envelope alone: the 14200 kN C0 and 920 kN Pu are specific to the NTN basic execution, and vibrating duty depends heavily on cage identity.
- Self-aligning does not mean unlimited misalignment: beyond the catalogue angle the outer ring's spherical travel is exhausted and the 7800 kN rating no longer applies.
- Minimum load must be maintained even at rest under vibration: an unloaded 231/530BK on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- The 7800/14200 kN ratings, 920 kN Pu and 633000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 231/530BK (basic); another maker's same-envelope part revises internal geometry, so re-verify ratings and cage before substitution on vibrating or rated drives.
Frequently asked questions
What are the dimensions and catalogue data of 231/530BK?
231/530BK is an NTN double-row spherical roller bearing to ISO 15: 530 mm bore, 870 mm OD and 272 mm width (20.866 × 34.252 × 10.709 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 7800 kN, C0 14200 kN, Pu 920 kN, grease limiting speed 310 r/min, oil 400 r/min, mass about 633000 g. It is open, with pressed-steel cage (standard execution) and a 1:12 tapered bore.
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
K denotes a 1:12 tapered bore. 231/530BK mounts on an adapter sleeve (or tapered shaft seat) and is driven up to the specified residual clearance; its cylindrical-bore counterpart in the same envelope and ratings is 231/530B.
What do EA and EM mean on NTN spherical roller bearings?
EA is the NTN standard-capacity/high-capacity execution with a pressed sheet-steel window cage; EM is the high-capacity execution with a one-piece machined brass cage. Both use the optimised symmetric-roller design, but cage identity changes mass, speed behaviour and suitability for duties like vibrating screens, so they are separate order numbers. 231/530BK is the basic execution.
What do D1 and W33 mean on 231/530BK?
231/530BK is listed without a D1/W33 outer-ring groove in 2203E; lubrication is supplied from the ring sides. D1 (NTN spelling) and W33 add the annular groove plus holes and are ordered as distinct suffixed executions of the same envelope.
How much misalignment and axial load can 231/530BK take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 23100 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 7800 kN C / 14200 kN C0 — but sustained pure axial load is not recommended because it unloads one row.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.