DEFINITION OF A LUBRICANT:
A lubricant is a substance that minimizes friction.
THE ROLE OF A LUBRICANT:
- Prevents wear
- Extends the life of engine parts
- Removes contaminants
- Reduces friction
- Retards corrosion
- Cools/carries off heat
Typically, lubricants contain from 70-99% base oils and 30-1% additives. Choosing the right base oils and additives can be determined by the application in which the lubricant is being used.
BASE OIL COMPOSITION:
Base oils are produced by refining crude oil. Crude oil can be mineral, plant/animal, or synthetic based.
THE REFINING PROCESS WORKS TO:
- Obtain desired viscosity, flash point and pour point.
- Removes undesirables, such as aromatics and waxes.
- Improves color
BASE OIL CLASSIFICATIONS:
Base oils are grouped into 5 classes:
Group I Solvent Neutral HVI stocks
Group II Hydrocracked / Hydroprocessed HVI stocks
Group III Severely Hydrocracked / Hydroprocessed VHVI stocks
Group IV All PAO’s
Group V All others not included in Group I,II,III or IV
With each increasing group classification, more and more intense processing is involved. The result is a higher quality, but more expensive base oil.
- Add performance properties to lubricants.
- Improve specific base oil properties.
- Lubricants contain many additives depending upon type and intended service.
For example, some engine oils may contain up to 15 additives.
TYPES OF ADDITIVES:
- Extreme pressure
- Rust inhibitors
- Oxidation inhibitors
- Pour point depressants
- Foam inhibitors
- Viscosity index improvers