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📥 Bearing Specs · Input
Quick presets:
Outside diameter of the bearing ring
Axial width of the bearing
Operating speed of the bearing in revolutions per minute
💡 How Ndn works: Ndn = N × dn, where dn = (D + bore) / 2 ≈ 0.75 × D for typical bearings. Higher Ndn → centrifugal force throws grease out → use less.
📤 Calculation · Result
Recommended grease quantity per re-greasing
3.6
grams
Base quantity Q₀ (no correction)
3.6 g
Ndn factor (D × N)
120,000
Speed range
Medium
Speed correction factor
65%
Re-greasing interval
every 8 hours
Recommended grease
MILLENIUM (NLGI 1.5-2)
⚠️ Important: Use only ASIANMAC-recommended grease (NLGI 1.5-2, dropping point >300°C, operation range -25 to +180°C). Wrong grease type causes premature bearing failure.
📐 The Formula
Source: ASIANMAC Roll Cassette Instruction Manual 2024-R5, page 13 (Greasing Standards section).
Q (grams) = (D × B) / 200
D = bearing outer diameter (mm)
B = bearing width (mm)
Q = base grease quantity in grams per re-greasing
Then apply speed correction based on Ndn factor:
Ndn < 50,000 RPM → Q_final = 100% × Q
50,000 < Ndn < 350,000 → Q_final = 65% × Q
Ndn > 350,000 RPM → Q_final = 30% × Q
📅 Re-Greasing Schedule (Standard)
| Operation Hours | Action | Notes |
|---|---|---|
| Every 8 hours | Re-grease bearings with calculated Q | Standard interval for continuous cold-rolling operation |
| Every 500 tons rolled | Inspect SKF NJ2316 mid-bearing (mandrel) | Replace if showing fatigue signs |
| Every shift change | Visual inspection of greasing system | Check grease nipples, hoses for clogging |
| Weekly | Test cooling pin shank diameter | CP25: 24.96-24.98 mm · CP26: 25.96-25.98 mm (replace if out) |
| Monthly | Clean greasing nipples in ethanol | Ensures clog-free operation |
🛢️ MILLENIUM Grease Specifications
| Property | Specification | Why It Matters |
|---|---|---|
| NLGI Grade | 1.5 to 2 | Right consistency for cold-rolling bearing speeds |
| Dropping Point | > 300°C | Doesn't melt during heating from rolling friction |
| Operation Temperature | -25°C to +180°C | Works in both winter shutdowns and full-load summer ops |
| 4-ball Wear (1h/40kg) | 0.5 mm | Low wear scar = bearing protection at peak load |
| Welded Load | 500 kgf | Resists film breakdown under shock loading |
⚠️ Critical Warnings
🔴 DO NOT use water jet to clean cassette — washes away grease, causes rust on cassette components
🔴 DO NOT use hammer/impact to remove bearings from Roll Holders — damages bearing seats and races. Use "knock-free" pull-style tools.
🟡 DO NOT use generic grease — only MILLENIUM-equivalent (NLGI 1.5-2, dropping point >300°C). Wrong grease can cause bearing seizure within hours.
🤝 Need MILLENIUM Grease or Spare 32008 Bearings?
ASIANMAC supplies all genuine cold-rolling line consumables to authorized distributors and partners.