Open gear grease is the heavy-EP solid-lubricant-loaded grease formulated for slow-speed high-load open gear drives — cement mill girth gear, ball mill drive, sugar mill crusher, mining shovel slewing gear, dragline boom. Distinguished by very high tackifier content (5-15% asphaltic / PIB), heavy sulphur-phosphorus EP, graphite + MoS2 solid lubricant load (3-10%) and sprayable NLGI 0/1 consistency. This guide gives the recommended aluminium complex BOM, Indian application map, and process.
| Component | Function | % (m/m) | Indian Supplier |
|---|---|---|---|
| Group I Bright Stock | Heavy base oil, high viscosity | 32.0% | IOCL Group I Bright |
| Group I SN500 | Carrier and viscosity reducer | 18.0% | IOCL / HPCL Group I |
| Asphaltic binder (Witmore / oxidised asphalt) | Tackifier / film former | 12.0% | Specialty asphaltic suppliers |
| Aluminium isostearate | Thickener (aluminium complex) | 6.0% | Specialty soap suppliers |
| Isostearic acid | Complexing acid for Al complex | 4.0% | Croda / specialty fatty acids |
| Sulphurised olefin EP (12% active S) | Heavy EP for boundary lubrication | 8.0% | Lubrizol Anglamol / BRB sulfides |
| Lead naphthenate / Zn-DTC EP | Heavy-EP supplementary | 4.0% | Specialty Pb / Zn additive suppliers |
| Graphite (natural flake 8-20 µm) | Solid lubricant — boundary protection | 5.0% | Indian graphite (Asbury, Carbon India) |
| MoS2 (technical grade) | Solid lubricant — low-friction boundary | 2.0% | MoS2 suppliers (Climax Mo, Lubrizol) |
| MoDTC FM | Friction modifier | 0.5% | Vanderbilt Vanlube 829 |
| Alkylated DPA aminic AO | Antioxidant | 0.8% | LANXESS Naugalube 438L |
| ASA + Ca sulfonate CI | Corrosion inhibitor | 1.2% | King K-Corr + Lubechem LC-DTR-CASULF |
| Polyisobutylene tackifier (Mn 2300) | High-MW tackifier | 5.0% | BASF Glissopal HR / INEOS Indopol |
| Calcium nitrite | Vapour-phase CI | 0.5% | Indian inorganic suppliers |
| Carbon black dye | Black appearance + UV resist | 2.0% | Carbon black suppliers |
| TOTAL | 100.0% | — | |
Process: dissolve asphaltic binder in heavy base oil + SN500 at 90 °C; in-situ Al complex saponification with isostearic acid + Al isostearate at 130 °C; cool to 70 °C; high-shear dispersing of EP / graphite / MoS2 / additives; final blend to NLGI 1. Drop >220 °C, 4-ball weld 500-630 kgf, Timken OK 60+ lbf. Ex-works cost ₹240-380 / kg at 5 MT batch.
Open gear grease is heavy-EP grease specifically formulated for slow-speed, high-load open gear drives — cement mill girth gear, sugar mill crusher drive, ball mill drive, dragline boom, mining shovel slewing gear. Applied by automatic spray system or manual brush onto exposed gear teeth.
Distinguished by: very high tackifier content (5-15% asphaltic / polyisobutylene for surface adhesion), heavy EP additive (sulphur-phosphorus 5-12% giving 4-ball weld 500+ kgf), often solid lubricant (graphite or MoS2 at 3-10%) for boundary lubrication, and sprayable NLGI 0/1 consistency for automatic spray system delivery.
NLGI 1 aluminium complex open gear grease BOM (%): Group I bright stock 32%, Group I SN500 18%, asphaltic binder 12%, aluminium isostearate 6%, isostearic acid 4%, sulphurised olefin EP 8%, lead naphthenate / Zn-DTC 4%, graphite 5%, MoS2 2%, MoDTC 0.5%, aminic AO 0.8%, ASA + Ca sulfonate CI 1.2%, PIB tackifier 5%, calcium nitrite 0.5%, carbon black 2%.
Process: dissolve binder in heavy base at 90 °C; saponify aluminium complex at 130 °C; cool; high-shear add solid lubricants and additives. NLGI 0/1, drop >220 °C, 4-ball weld 500-630 kgf, Timken 60+ lbf.
Both are solid-lubricant additives that give boundary lubrication when the EP oil film breaks under heavy load. Graphite (natural flake, 8-25 µm) is cheap, works in water-contaminated environments, gives black appearance. Treat 3-15%. MoS2 (molybdenum disulphide) is more expensive but lower friction (μ 0.05-0.07 vs graphite 0.10-0.15), better at high temperature. Treat 1-5%.
Premium open gear grease uses both. Cement mill girth gear standardises on graphite-heavy formulation; mining shovel slewing uses MoS2-heavy.
Three application methods. (1) Automatic spray system — most common for cement mill, ball mill. Pneumatic spray gun delivers metered shot of NLGI 0/1 grease onto rotating gear teeth every 5-15 minutes. Grease must be pumpable through long pipe runs.
(2) Brush application — for slow-speed sugar mill drives, dragline. Heavy brush load applied during planned shutdown. (3) Centralised lubrication — single feed system distributes pre-metered grease through manifold to multiple points.
Cement mill girth gear — largest Indian segment. Ball mill drive in mineral processing. Sugar mill crusher drive. Mining shovel slewing, dragline boom. Dredger and conveyor drive. NTPC ash handling system.
Brands: SKF LGOG 2, Shell Malleus, Mobil OGL, IOCL Servoplex Open Gear, Mak HD Open Gear, Klüber Grafloscon. Indian volume ~25,000 MT/year. Lubechem custom LC-GR-AL-OG ₹240-380/kg at 5+ MT batch.
Aluminium complex (from aluminium isopropoxide + isostearic acid + benzoic acid) is the thickener of choice for open gear grease because: (1) high temperature stability (drop >220 °C), (2) excellent water resistance, (3) tacky inherent texture — sticks to gear teeth without runoff, (4) compatible with asphaltic binders and solid lubricants, (5) good corrosion protection.
Alternative thickeners for open gear: lithium complex, bentonite organoclay (very high temp specialty), asphaltic-only (no soap, polymer-only).
Share your application (cement girth gear / ball mill / sugar mill / mining), spray vs brush, volume and budget. We respond within one business day with the BOM and ex-works cost.