Industrial Oil Grades refer to the systematic classification of lubricating oils used in industrial machinery, processing equipment, and heavy-duty systems. These grades are defined primarily by viscosity, performance characteristics, base oil type, and application-specific requirements.
Unlike automotive oils, industrial oils are designed for continuous operation, high-load and high-pressure environments, extreme temperatures, long drain intervals, and precise equipment tolerances. Proper oil grading helps industries maximize equipment efficiency, reduce downtime, and extend asset life.
Major Classification Systems for Industrial Oils
1. ISO Viscosity Grade (ISO VG – Most Widely Used)
Defined by ISO 3448, this system classifies oils based on kinematic viscosity at 40°C.
| ISO VG | Typical Applications |
|---|---|
| 22 | Light hydraulic & precision systems |
| 32 | High-speed hydraulics, cold climates |
| 46 | General industrial hydraulics |
| 68 | Gearboxes, heavy hydraulics |
| 100 | Circulating systems, compressors |
| 150 – 680 | Heavy gear & load-bearing systems |
2. DIN & International Standards
✔ DIN 51524 – Hydraulic oils (HL, HLP, HVLP)
✔ DIN 51517 – Gear oils (CL, CLP, CKS)
✔ ISO HM / HV / HG – Hydraulic oil performance classifications
Key Characteristics of Industrial Oil Grades
Optimized Viscosity
Maintains correct oil film thickness, prevents metal-to-metal contact, improves energy efficiency, and ensures stable operation across temperature fluctuations.
High Oxidation Stability
Resists oxidation under heat and oxygen exposure, preventing sludge, varnish, and acidic by-products while supporting extended drain intervals.
Wear & Corrosion Protection
Specialized additive systems protect ferrous and non-ferrous metals, reducing adhesive and abrasive wear and preventing rust caused by moisture.
Thermal & Mechanical Durability
Retains viscosity stability and load-carrying capacity under heavy loads, high pressures, and continuous duty cycles.
Refining & Production Properties
Base Oil Refining Technologies
✔ Solvent Extraction – removes aromatics and improves oxidation resistance
✔ Hydrocracking & Hydrotreating – produces cleaner, more stable base oils
✔ Synthetic Base Oils (PAO / Esters) – superior thermal stability and long service life
Additive Formulation
Industrial oils are blended with anti-wear (AW), extreme-pressure (EP), anti-foam, rust inhibitors, oxidation inhibitors, and demulsifiers based on equipment requirements.
Types of Industrial Oil Grades
Hydraulic Oils
ISO VG 22, 32, 46, 68 | HL, HLP, HVLP – presses, CNC machines, construction equipment
Gear Oils
ISO VG 68 – 680 | DIN CL / CLP – gearboxes, conveyors, crushers
Compressor Oils
ISO VG 32, 46, 68, 100 – air, gas & refrigeration compressors
Turbine Oils
ISO VG 32, 46, 68 – steam, gas & hydro turbines
Circulating Oils
ISO VG 68 – 460 – steel mills, paper machines, large bearings
Specialty Industrial Oils
Way oils, spindle oils, quenching oils, transformer oils, heat transfer oils
Typical Performance Properties
| Property | Importance |
|---|---|
| Viscosity @ 40°C | Flow & lubrication performance |
| Viscosity Index | Temperature stability |
| Flash Point | Safety & high-temperature resistance |
| Pour Point | Cold-start fluidity |
| Oxidation Life | Oil longevity |
| Demulsibility | Water separation capability |
| Foam Control | System efficiency & stability |
Industrial Applications
✔ CNC machining & injection molding
✔ Textile & paper machinery
✔ Steel, cement, mining & power plants
✔ Construction equipment & hydraulic presses
✔ Marine & offshore circulating systems
Importance of Correct Oil Grade Selection
✔ Maximizes equipment life
✔ Reduces energy consumption
✔ Prevents premature failures
✔ Minimizes maintenance costs
✔ Improves operational efficiency
Incorrect grade selection can lead to overheating, poor lubrication, accelerated wear, and unplanned equipment downtime.