1. What It Is:
Base oil is the primary raw material used in the production of lubricants, such as engine oils, greases, and hydraulic fluids. It is derived from refined crude oil or synthetic processes, and serves as the foundation for blending with additives.
2. Classification (API Groups):
Group I:
- Solvent refined
- Low performance, used in industrial oils
- Saturates <90%, sulfur >0.03%, VI: 80–120