Lubricant and Lubrication Fundamentals

Mustafa Ali

LUBRICANTS AND LUBRICATION FUNDAMENTALS

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TABLE OF CONTENTS Types of Lubricants -----------------------------------------------------------------------------3 Solid Lubricants----------------------------------------------------------------------------------3 Liquid Lubricants--------------------------------------------------------------------------------4 Base Stock-------------------------------------------------------------------------------4 Additives---------------------------------------------------------------------------------6 Functions of Lubricant-----------------------------------------------------------------15 Fluid Film Lubrication-----------------------------------------------------------------16 Oil Characteristics----------------------------------------------------------------------17 Grease---------------------------------------------------------------------------------------------23 Filtration------------------------------------------------------------------------------------------26 Methods of lube Application ------------------------------------------------------------------27 Oil Testing----------------------------------------------------------------------------------------32 Useful Tables-------------------------------------------------------------------------------------35 Bibliography--------------------------------------------------------------------------------------51

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1. TYPES 

Solid



Liquid



Gas

2. SOLID LUBRICANTS

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3. Liquid Lubricants 3.1 Composition of liquid Lubricants Base stock + Additives = Lubricant

3.1.1 Base Stock Crude oil is distilled to yield different fractions one of which is the base stock for finished lubricants. The base stock is manufactured by two processes namely separation and conversion.

Separation involves division of the crude oil into its different fractions while conversion takes into account the different processes required to refine the base stock. Usually separation involves Pre-eating, Fractional distillation, Vacuum distillation, Propane de-asphalting, Furfural extraction, solvent de-waxing (through MEK) and clay/hydro-finishing. Conversion involves Vacuum distillation, Hydro-cracking (Group II and III)/ Hydrogen De-waxing (Group I and II) and Hydro-finishing.

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3.1.1.1 Classification of Base Stocks A Group I Solvent Refined II Hydro-finished III Hydro-cracked IV Poly Alpha Olephin V All Others

Saturates (%) 90 >90

Sulfur (%) >0.03 reduction in viscosity

Flash point test

Contamination with solvents

If low then flash point test

Contamination with solids

Pentane insolubles, Benzene Insolubles

Water contamination

Crackle Test >110 C

10.1 Wear Analysis A. Spectroscopy 1. Emission Oil + Electric arc from C electrode (frequency and intensity of light) 

Rotode



Inductively coupled plasma (ICP)-----(nebula + hot argon plasma)

2. Atomic Absorption Oil + Acetylene flame + Concentrated light It works on the principle of light absorption. 32

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B. Magnetic Plug Techniques Equipment  Magnetic plug with electrodes  Chip detector to indicate metal parts  Electric heater to burn small fuzz If warning 

Not cancelled => large chip flakes =>danger



Occurring rapidly => fine and continuous debris



Cancelled => fine but broken debris

C. Ferrography

Wear particles are deposited on the slide. The magnet below the chip retains them even when the substrate has been washed away from the chip. Stronger particles are deposited first and along the axis.

D. Rotary Particle Depositor

The oil is dropped on the centre of the magnet from where it moves radially outwards. 33

Mustafa Ali The largest and most highly ferromagnetic particles gather in the inner most circle. Particles of decreasing susceptibility deposit in the outer circles.

10.2 Contaminant Warning Levels

Test

Warning Limit

Viscosity -cSt @ 40C

25% change vs. the new oil viscosity

-cSt @ 100 C

15% change vs. the new oil viscosity

Coolant

Any positive identification

Water

Greater than 0.1 %

Dilution

Greater than 5%

Insolubles

0.5% or more

Total Acid Number

More than 5 units (motor oil) or 1 unit (industrial oil)

Total Base Number

No lower than 3 to 4 units

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11. USEFUL TABLES

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12. BIBLIOGRAPHY 1. 2. 3. 4. 5.

Fundamentals of Fluid Film Lubrication- Marcel Dekker-2004. Lubrication Fundamentals-D.M.Pirro & A.A.Wessol-Exxon Mobil Corporation-2001. Mechanical Engineer’s Reference Book-E. H. Smith-Butterworth Heinemann-1994 Lubrication and Lubricant Selection-A.R.Lansdown-TIPS Series-2004 Lubrication and Maintenance of Industrial Machinery-Robert Gresham & G.E.TottenTaylor and Francis Group-2009 6. Lubricant Additives Chemistry and Application-Leslie R. Rudnick- Taylor and Francis Group-2009 7. U.S Army Lubricants-U.S. Army Corps of Engineers 8. Timken Lubrication Guide-Torrington & Fafnir 9. Petro Canada Lubricants Handbook-2005 10. Engineering Tribology-G.W.Stachowiak & A.W.Batchelor-Elsevier-1993 11. Tribology in Machine Design-T.A. Stolarski-Butterworth Heinemann-1990 12. Tribology: Friction, Wear and Lubrication-Bharat Bhushan-CRC Press-2000

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