Base Oil
Base Oil
Group I, II and III base stocks — the refined mineral foundation that makes up the bulk of every finished lubricant.
Base oil is what a lubricant mostly is. A finished engine oil is typically seventy to ninety per cent base stock, with the additive package supplying detergency, anti-wear protection and viscosity control on top. The quality of that base stock sets the ceiling on what the additives can achieve.
Addam Energy supplies base oil to blenders, grease manufacturers, metalworking fluid producers and process industries, from single tank containers through to bulk cargo parcels.
How base oils are classified
The American Petroleum Institute divides base stocks into five groups by saturate content, sulphur content and viscosity index. The higher the group, the more thoroughly the aromatic and sulphur-bearing molecules have been removed, and the better the oxidation stability and viscosity–temperature behaviour.
Group I is solvent refined and still dominates industrial oils, greases and process applications. Group II is hydrotreated, much cleaner, and is now the standard for automotive engine oils. Group III is severely hydrocracked to a viscosity index above 120 and is used where synthetic-level performance is required from a mineral stock.
The API groups
- Group I — under 90% saturates, over 0.03% sulphur, VI 80–120. Solvent refined.
- Group II — over 90% saturates, under 0.03% sulphur, VI 80–120. Hydrotreated.
- Group III — over 90% saturates, under 0.03% sulphur, VI above 120. Hydrocracked.
- Group IV — polyalphaolefins, fully synthetic.
- Group V — everything else: esters, polyalkylene glycols, naphthenics, white oils.
Viscosity grades supplied
- SN 70 / SN 80 — light neutral for hydraulic and light spindle oils
- SN 150 — light grade for automatic transmission and light engine oils
- SN 350 — medium neutral, the general-purpose blending stock
- SN 500 — the most widely traded grade, engine and industrial oils
- SN 600 — heavier neutral for gear oils and heavy-duty applications
- SN 650 / BS 150 — bright stock for greases, gear oils and marine cylinder oils
Where it goes
- Automotive engine oils, gear oils and transmission fluids
- Industrial hydraulic, turbine, compressor and circulating oils
- Metalworking fluids, cutting oils and quenching oils
- Grease manufacture across lithium, calcium and complex soap thickeners
- Transformer and electrical insulating oils
- Process oils for rubber, polymer and textile manufacture
- Carrier oil in agricultural and industrial formulations
Quality and handling
Every parcel ships with a certificate of analysis covering kinematic viscosity at 40 °C and 100 °C, viscosity index, flash point, pour point, colour, density, sulphur content and total acid number. Store in clean, dry, dedicated tankage away from heat and direct sun, and keep water out — moisture ingress is the single most common cause of off-specification base oil at the blending plant.
Typical specification
| Kinematic viscosity @ 40 °C | ASTM D445 — to grade |
|---|---|
| Kinematic viscosity @ 100 °C | ASTM D445 — to grade |
| Viscosity index | ASTM D2270 — 95 minimum, Group I |
| Flash point (COC) | ASTM D92 — 220 °C minimum, SN 500 |
| Pour point | ASTM D97 — −9 °C maximum |
| Colour (ASTM) | ASTM D1500 — 2.0 maximum |
| Total acid number | ASTM D974 — 0.05 mg KOH/g maximum |
| Sulphur content | ASTM D4294 — by group |
Values are indicative and given for guidance. Contract specification is agreed in writing and certified per batch on the certificate of analysis issued with each shipment.
