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Product Description
950mm bore · 1360mm OD · 880mm width · GCr15 / 52100 · Rolling Mill Work/Backup Rolls · Crushers · Vibrating Screens
Parameter | Value |
Part Number | 3820/950 |
Cross Reference | 20771/950 |
Type | Four Row Tapered Roller Bearing |
Bore (d) | 950 mm |
OD (D) | 1360 mm |
Width (B) | 880 mm |
Roller Complement | 7.5 mm (roller diameter reference) |
Material | GCr15 / AISI 52100 / 100Cr16 / SUJ2 / 683/XVIII / SKF3 |
Precision | DIN620 P0 / P6 / P5 · ABEC-1 / 3 / 5 |
Clearance | C0 / C2 / C3 / C4 / C5 |
Sealing | Open (standard) · Shielded / Sealed on request |
HS Code | 8482800000 |
Brand | Nexans Bearings |
The 3820/950 (20771/950) is a 950×1360×880mm four-row tapered roller bearing — one of the largest bearing configurations in industrial production. Both designations refer to the identical bearing: 3820/950 is the GB/ISO standard; 20771/950 is the alternative cross-reference.
Four-row tapered roller bearings are used almost exclusively in rolling mill work roll and backup roll neck applications — where extreme radial separating forces, bidirectional axial loads, and fixed roll neck housing diameters make this the only viable bearing solution. The four-row tandem-opposed geometry delivers approximately twice the radial load capacity of a comparable double-row bearing within the same radial envelope.
Secondary applications: large primary crushers (jaw, gyratory), vibrating screens, and heavy printing machinery.
Internal construction: four cups + four cones + spacer rings — separable, field-maintainable.
Parameter | Double Row (3519 series) | Four Row (3820/950) |
Row count | 2 | 4 |
Primary application | Gearboxes, mining, general heavy industry | Rolling mill work/backup rolls |
Radial load capacity | High | Extreme — ~2× double row at same bore |
Axial load direction | Bidirectional | Bidirectional (2 rows per direction) |
Operating speed | Low to moderate | Low to moderate (rolling mill speeds) |
Compactness | Standard | Maximum — optimized for roll neck housing |
Industry | Typical Use | Selection Reason |
Steel Rolling Mills | Work roll necks, backup roll necks | Extreme radial separating force; max compactness in roll neck |
Aluminium Rolling Mills | Hot mill work rolls, cold mill backup rolls | High rolling force; thermal cycling; coolant contamination |
Copper & Non-Ferrous Mills | Work roll necks, tension reel mandrels | Combined load; precision alignment |
Primary Crushers | Jaw crusher eccentric shafts, gyratory mainshafts | Extreme radial impact; bidirectional axial; contamination |
Vibrating Screens | Large exciter shafts, vibrating feeder drives | High dynamic radial load; cyclic shock |
Heavy Printing Machinery | Impression cylinder roll necks | Combined load; precision; continuous operation |
Parameter | Value | Notes |
Bore (d) | 950 mm | Among the largest in four-row tapered production |
OD (D) | 1360 mm | 410mm radial cross-section depth |
Width (B) | 880 mm | Near-square: four full roller rows + spacers |
Width-to-Bore Ratio | 0.926 | Near 1:1 — characteristic of four-row rolling mill bearings |
Roller Complement | 7.5 mm reference | Optimized for 950mm bore load distribution |
The 880mm width on a 950mm bore (ratio 0.926) is characteristic of the four-row class — accommodating four complete roller rows with raceways, cages, and spacer rings within a single compact housing envelope.
Parameter | Value | Notes |
Precision | P0 / P6 / P5 | Hot mill: P0; cold mill work rolls: P5/P6 |
Clearance | C0/C2/C3/C4/C5 | C3/C4 standard for rolling mill thermal expansion |
Lubrication | Circulating oil (rolling mills) | ISO VG 220–460; EP NLGI 2–3 grease for crushers/screens |
Operating speed | Low to moderate | Rolling mill work/backup roll speeds |
Temperature | –20°C to +150°C | Heat-stabilized steel on request |
Sealing | Open / Shielded / Sealed | Rolling mills typically use labyrinth seals in housing |
Q: 3820/950 vs 20771/950 — what's the difference?
Same bearing. 3820/950 = GB/ISO designation. 20771/950 = alternative cross-reference.
Q: Why are four-row tapered roller bearings used almost exclusively in rolling mills?
The roll neck housing diameter is fixed by the roll body diameter — no room to increase bearing OD. The four-row tapered roller bearing is the only type that fits within this fixed radial envelope while carrying the extreme work roll separating forces (tens of thousands of kN). No other bearing type matches this load-capacity-to-radial-space ratio at rolling mill bore sizes.
Q: Precision grade — cold mill vs hot mill?
Hot mill work/backup rolls: P0 (ABEC-1) — maximum load capacity priority
Cold mill work rolls: P5 (ABEC-5) or P6 (ABEC-3) — dimensional accuracy and surface finish of rolled product
Cold mill backup rolls: P6 (ABEC-3) Confirm with your rolling mill OEM equipment manual or roll neck drawing.
Q: Lubrication — rolling mill vs crusher/screen?
Rolling mills: circulating oil system, ISO VG 220–460 — continuous filtration, cooling, and contamination flushing. Crushers / vibrating screens: EP-additive grease, NLGI Grade 2–3. Confirm with OEM equipment manual.
Q: What does the 7.5mm roller complement reference mean?
The 7.5mm figure is the roller diameter reference parameter in the four-row series designation system — defines the roller size class used to calculate load ratings, limiting speeds, and fatigue life for the 950mm bore geometry.
Q: MOQ and lead time?
MOQ: 1 piece. Stock items: 5–7 business days. Made-to-order: typically 4–8 weeks for ultra large-bore four-row production. FOB Qingdao / CIF / EXW. Full engineered wooden crating and heavy-lift documentation included as standard.
Q: OEM / private label available?
Yes — custom box artwork, laser-engraved logo on bearing ring, fully branded packaging. All IP rights belong to you. MOQ and pricing on request.
Part No. | Dimensions | Type | Application |
3519/900 | 900×1180×275mm | Double Row Tapered | Rolling mills, mining, tunnelling |
3519/800 | 800×1060×270mm | Double Row Tapered | Rolling mills, mining, energy |
3519/750 | 750×1000×264mm | Double Row Tapered | Rolling mills, mining, gearboxes |
3519/710 | 710×950×240mm | Double Row Tapered | Rolling mills, mining, heavy drives |
3519/670 | 670×900×240mm | Double Row Tapered | Rolling mills, mining, gearboxes |
Website | |
+86-155-6283-9480 | |
Location | Liaocheng, Shandong, China |
