230-630BK bearing: complete specifications & equivalents
The 230-630BK is a ISO 15 radial bearing sized 630 x 920 x 212 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 630 mm |
| Outer diameter D | 920 mm |
| Width B | 212 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 6550 kN |
| Basic static load rating C0 | 13000 kN |
| Fatigue load limit Pu | 950 kN |
| Limiting speed (mechanical) | 310 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 464000 g |
| Manufacturer designation | NTN 230/630BK |
| 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 | 24.803 in |
|---|---|
| Outer diameter D | 36.22 in |
| Width B | 8.346 in |
| ISO bore code | 30 |
| Radial section height (D−d)/2 | 145 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) | 36 of 46 |
| Bore above smallest 23000-series size | 560 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 230-630B | 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 230-630B — 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 230-630BK model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 230/630BK denotes the 630 mm bore spherical roller bearing (6550 kN C / 13000 kN C0) in the 23000 series, the self-aligning choice for heavy combined load. Digit by digit the code reads as spherical-roller dimension series plus 630 mm bore; the 212 mm width is the wide ISO 15 section, which is why spherical rollers interchange dimensionally but not in cage or rating detail. Suffix reading on 230/630BK: the bare number is the standard open execution; K marks the 1:12 tapered bore; 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 1.98 (13000/6550 kN) reflects the heavy static and shock proportioning of 230/630BK; size the equivalent load at the required L10 with shock factor for the application. On vibrating-duty shafts verify the radial clearance class and cage choice at order time; the open 230/630BK leaves sealing and the C3/C4 clearance decision to the application drawing.
Typical equipment & failure modes
Common applications
- large SAG/ball-mill trunnion and pinion shafts
- heavy vibrating screens and grizzly feeders
- offshore and marine propulsion shaftlines
- large wind-turbine main-shaft arrangements
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- pressed EA cage fatigue under sustained vibration when minimum load is not maintained
- 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
- false brinelling on stopped machines exposed to screen or crusher vibration
Selection pitfalls — read before you substitute
- At 630 mm bore 230/630BK 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.
- Self-aligning does not mean unlimited misalignment: beyond the catalogue angle the outer ring's spherical travel is exhausted and the 6550 kN rating no longer applies.
- Open spherical rollers swallow dust in mining duty; specify labyrinth or taconite seals externally, or the 310 r/min grease rating is lost to abrasive wear long before fatigue.
- The 1:12 tapered bore is the only difference from the cylindrical-bore 230/630B: envelopes and ratings match, but drive-up tooling, sleeve and seat do not — never mix the two mounting methods.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 212 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- The 6550/13000 kN ratings, 950 kN Pu and 464000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 230/630BK (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 230/630BK?
230/630BK is an NTN double-row spherical roller bearing to ISO 15: 630 mm bore, 920 mm OD and 212 mm width (24.803 × 36.22 × 8.346 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 6550 kN, C0 13000 kN, Pu 950 kN, grease limiting speed 310 r/min, oil 400 r/min, mass about 464000 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. 230/630BK 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 230/630B.
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. 230/630BK is the basic execution.
What do D1 and W33 mean on 230/630BK?
230/630BK 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 230/630BK 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 — 6550 kN C / 13000 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.