230-670B bearing: complete specifications & equivalents
The 230-670B 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 | 594000 g |
| Manufacturer designation | NTN 230/670B |
| 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 |
|---|---|---|---|
| 230-670BK | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23000-series envelope, cage and ratings; this is the cylindrical-bore execution of the tapered-bore 230-670BK (K/K30 sleeve or tapered-seat mounting). 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 230-670B model number is decoded
230/670B is the basic execution of NTN's spherical roller range for a 670 mm shaft — 7300 kN basic dynamic capacity in a 594000 g, open ISO 15 envelope. Numbering ties 230/670B to its envelope and execution: same-number EA versus EM or plain variants share the 670 mm bore but differ in cage and sometimes mass, so they are quoted as separate articles. Suffix reading on 230/670B: the bare number is the standard open execution; B marks the standard large-bore internal design on slash-size 230–232 series; quote the full code because each suffix is a distinct article. Selection: the C0/C ratio of 2.00 (14600/7300 kN) reflects the heavy static and shock proportioning of 230/670B; size the equivalent load at the required L10 with shock factor for the application. Fit the cylindrical-bore 230/670B with the inner ring heated (max 120 °C) for the shaft interference; the outer ring slides into the housing with its spherical seat able to pivot after seating.
Typical equipment & failure modes
Common applications
- offshore and marine propulsion shaftlines
- large wind-turbine main-shaft arrangements
- steel-mill and heavy crusher main shafts
- mining shovel and dragline swing shafts
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
- sliding wear and heat when relubrication intervals ignore the groove (D1/W33) supply path
- rolling-contact fatigue after the catalogue L10 life at the actual load
- asymmetric wear on the two roller rows from sustained angular misalignment beyond the self-aligning range
Selection pitfalls — read before you substitute
- At 670 mm bore 230/670B 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.
- Adapter-sleeve mounting requires the correct sleeve series and locknut for the 670 mm shaft; a sleeve sized to bore alone ignores thread, width and the oil-injection option on large K30 seats.
- Do not confuse EA and EM at the same number: 230/670B carries basic; swapping to the other cage execution changes mass, speed behaviour and sometimes suitability for vibration, even though the 670×980 mm envelope is identical.
- Oil relubrication toward 360 r/min needs drain and level design; flooding the 230 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 230 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- The 7300/14600 kN ratings, 1000 kN Pu and 594000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 230/670B (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 230/670B?
230/670B 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 594000 g. It is open, with pressed-steel cage (standard execution).
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
230/670B has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 230/670BK (K = 1:12, or K30 = 1:30 on the wide series), intended for adapter/withdrawal-sleeve mounting.
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. 230/670B is the basic execution.
What do D1 and W33 mean on 230/670B?
230/670B 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 230/670B 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.