232-670B bearing: complete specifications & equivalents
The 232-670B is a ISO 15 radial bearing sized 670 x 1220 x 438 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 | 1220 mm |
| Width B | 438 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 17900 kN |
| Basic static load rating C0 | 32000 kN |
| Fatigue load limit Pu | 1770 kN |
| Limiting speed (mechanical) | 220 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2270000 g |
| Manufacturer designation | NTN 232/670B |
| 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 & 23200-series range
| Bore d | 26.378 in |
|---|---|
| Outer diameter D | 48.031 in |
| Width B | 17.244 in |
| ISO bore code | 32 |
| Radial section height (D−d)/2 | 275 mm |
| Smallest bore in 23200-series | 90 mm |
| Largest outer diameter in 23200-series | 1360 mm |
| Width range across 23200-series | 52.4–475 mm |
| Bore position in 23200-series (smallest first) | 32 of 34 |
| Bore above smallest 23200-series size | 580 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 232-670BK | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23200-series envelope, cage and ratings; this is the cylindrical-bore execution of the tapered-bore 232-670BK (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 232-670B model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 232/670B denotes the 670 mm bore spherical roller bearing (17900 kN C / 32000 kN C0) in the 23200 series, the self-aligning choice for heavy combined load. Numbering ties 232/670B 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. Open by design, 232/670B requires application seals and a grease or oil system; NTN vibrating-duty executions of this envelope are selected with cage and clearance choices that are separate order codes. The 275.0 mm section height hosts the spherical roller geometry; shaft and housing fillet radii must clear the chamfer table so the 438 mm-wide ring seats fully on both sides. Supply grease through the outer-ring feature during commissioning and at the calculated interval, rotating the 670 mm bore assembly by hand to distribute it across both rows.
Typical equipment & failure modes
Common applications
- heavy vibrating screens and grizzly feeders
- offshore and marine propulsion shaftlines
- large wind-turbine main-shaft arrangements
- steel-mill and heavy crusher main 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
- fretting corrosion between adapter sleeve and tapered bore when the drive-up is insufficient
Selection pitfalls — read before you substitute
- At 670 mm bore 232/670B 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.
- Never substitute 232/670B by envelope alone: the 32000 kN C0 and 1770 kN Pu are specific to the NTN basic execution, and vibrating duty depends heavily on cage identity.
- Oil relubrication toward 280 r/min needs drain and level design; flooding the 438 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- Minimum load must be maintained even at rest under vibration: an unloaded 232/670B on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- Self-aligning does not mean unlimited misalignment: beyond the catalogue angle the outer ring's spherical travel is exhausted and the 17900 kN rating no longer applies.
- The 17900/32000 kN ratings, 1770 kN Pu and 2270000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 232/670B (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 232/670B?
232/670B is an NTN double-row spherical roller bearing to ISO 15: 670 mm bore, 1220 mm OD and 438 mm width (26.378 × 48.031 × 17.244 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 17900 kN, C0 32000 kN, Pu 1770 kN, grease limiting speed 220 r/min, oil 280 r/min, mass about 2270000 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?
232/670B has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 232/670BK (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. 232/670B is the basic execution.
What do D1 and W33 mean on 232/670B?
232/670B 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 232/670B take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 23200 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 17900 kN C / 32000 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.