230-670BK bearing: complete specifications & equivalents
The 230-670BK is a ISO 15 radial bearing sized 670 x 980 x 230 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 670 mm |
| Outer diameter D | 980 mm |
| Width B | 230 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 7300 kN |
| Basic static load rating C0 | 14600 kN |
| Fatigue load limit Pu | 1000 kN |
| Limiting speed (mechanical) | 280 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 573000 g |
| Manufacturer designation | NTN 230/670BK |
| 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 & 23000-series range
| Bore d | 26.378 in |
|---|---|
| Outer diameter D | 38.583 in |
| Width B | 9.055 in |
| ISO bore code | 30 |
| Radial section height (D−d)/2 | 155 mm |
| Smallest bore in 23000-series | 70 mm |
| Largest outer diameter in 23000-series | 1580 mm |
| Width range across 23000-series | 27–345 mm |
| Bore position in 23000-series (smallest first) | 37 of 46 |
| Bore above smallest 23000-series size | 600 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 230-670B | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23000-series envelope, cage and ratings; this is the tapered-bore execution (K, 1:12) of the cylindrical-bore 230-670B — 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 230-670BK model number is decoded
230/670BK is an NTN double-row spherical roller bearing: two rows of symmetric rollers on a sphered outer raceway, 670×980×230 mm to ISO 15, with pressed-steel cage (standard execution). Reading the full code: the number gives the 670×980 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 plain outer ring (no D1/W33 groove) makes relubrication part of the design: fresh grease reaches the rolling elements through the outer-ring feature rather than relying solely on end-side packing. Selection: the C0/C ratio of 2.00 (14600/7300 kN) reflects the heavy static and shock proportioning of 230/670BK; size the equivalent load at the required L10 with shock factor for the application. Check the self-aligning movement after fitting: the housing should pivot freely around the sphered outer raceway; a pinched outer ring removes the alignment capacity the bearing was selected for.
Typical equipment & failure modes
Common applications
- steel-mill and heavy crusher main shafts
- mining shovel and dragline swing shafts
- cement-rotary-kiln support and trunnion rolls
- large SAG/ball-mill trunnion and pinion shafts
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- machined EM cage wear from inadequate oil film at the cage-guiding surfaces
- sliding wear and heat when relubrication intervals ignore the groove (D1/W33) supply path
- brinelling from static overload or a hammer blow during sleeve mounting
- hard-particle indentation through the open arrangement in dusty mining duty
Selection pitfalls — read before you substitute
- At 670 mm bore 230/670BK 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.
- Minimum load must be maintained even at rest under vibration: an unloaded 230/670BK on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- The 1:12 tapered bore is the only difference from the cylindrical-bore 230/670B: envelopes and ratings match, but drive-up tooling, sleeve and seat do not — never mix the two mounting methods.
- K and K30 are different tapers — K is 1:12 and K30 is 1:30 on the wide series; an adapter sleeve for one will not mount the other 670 mm bearing, and drive-up procedures differ.
- K and K30 are different tapers — K is 1:12 and K30 is 1:30 on the wide series; an adapter sleeve for one will not mount the other 670 mm bearing, and drive-up procedures differ.
- The 7300/14600 kN ratings, 1000 kN Pu and 573000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 230/670BK (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 230/670BK?
230/670BK is an NTN double-row spherical roller bearing to ISO 15: 670 mm bore, 980 mm OD and 230 mm width (26.378 × 38.583 × 9.055 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 7300 kN, C0 14600 kN, Pu 1000 kN, grease limiting speed 280 r/min, oil 360 r/min, mass about 573000 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. 230/670BK 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 230/670B.
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. 230/670BK is the basic execution.
What do D1 and W33 mean on 230/670BK?
230/670BK 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 230/670BK take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 23000 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 7300 kN C / 14600 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.