Testing Of Lubes And Its Significance Nov 2011

Testing of Lubricants
& its significance

Hussam Adeni

Lube.specialist@gmail.com

Testing of lubricants
& its significance

Type of lubricants
Automotive Lubricants
Industrial lubricants

Hussam Adeni Lube.specialist@gmail.com

& its significance

Automotive Lubricants
• Engine Oils
• Gear Oils
• Brake Fluids
• Coolants
• Automatic Transmission Fluid


& its significance

Industrial Lubricants
• Metal working Oils
• Neat, Soluble, Synthetic,
• Semi synthetic
• Metal Deformation
• Heat Treatment
• Corrosion Preventives
• Dewatering Fluids
• Industrial Cleaners
• Compressor Oils

& its significance

Industrial Lubricants
• Hydraulic Fluids
• Industrial Gear Oils
• Turbine Oils
• Refrigeration Oils
• Greases
• Rock Drill Oils
• Electrical Oils
• Process Oils
• Ginning Oils

Routine Lubricant tests

Gear Oils

• Color
• Condition / Appearance
• Acidity
• Water content
• Wear Metal Analysis (for used Oils)



Turbine Oils

• Color
• Condition Appearance
• Acidity
• Water content
• Kinematic Viscosity at 40 °C
• Demulsification value


Compressor Oils

• Color
• Condition Appearance
• Acidity
• Water content



Refrigeration Oils

• Color
• Pour /Floc point
• Dielectric strength
• Acidity
• Water content

Common Lubricant tests

Appearance

• Fresh Oil is bright and clear
• Presence of water or other contaminants make
the oil hazy / cloudy



Density
IP 160 /ASTM D 1298

• Expressed as gm/cc
• Measured at 15° C
• Specific gravity ( or Relative density) is the
density of the substance relative to density of
water



Colour
ASTM D 1500

• Expressed on scale of 0.0 to 8.0, latter being
the darkest – Lovibond Colour Comparator.
• Natural colour of lighter oils pale/yellow or
darker for heavier (high Vis. Oils)
• During usage and onset of oxidation, oil is
darkened by products of combustion



Kinematic Viscosity (KV)
IP 71 / ASTM D 445

• Viscosity of a liquid is its resistance to flow &
is directly related/affected by temperature
• Viscosity decreases with increase in
temperature & increases with decrease in
temperature.
• Kinematic Viscosity (KV) is expressed in
centistokes (cSt)
• ISO Viscosity grades KV @ 40° C and 100°C


Viscosity Index ( VI)
IP 226 / ASTM D 2270
• VI of an oil is calculated from its Kinematic
viscosities at 40° C and 100°C
• High VI – Oils exhibit small decrease in KV with
increase in temperature
• Low VI - Oils exhibit large decrease in KV with
increase in temperature.
• Paraffinic Oils – have high VI’s ( 80 – 100)
• Naphthenic Oils – have low VI’s ( 0 – 30)


Flash Point (COC or PMCC)
IP 34 / ASTM D 93, IP 36 / ASTM D 92

• Lowest temperature at which a vapour above
liquid will ignite when flame is applied
• Expressed in Degrees Celsius (°C)
• IP 34 – Pensky Marten Closed Cup (PMCC)
• IP 36 – Clevland Open Cup ( COC)
• Decrease on Flash Point – indicates thermal
cracking of oil



Total Base Number (TBN)
IP 276 / ASTM D 2896
• Expressed as mgKOH/gm
• It is the alkaline reserve incorporated into an
oil to neutralize acid products of combustion
derived from sulfur in the fuel.
• TBN decrease result of
• Oil oxidation
• Water contamination
• Fuel contamination
• TBN depletion can be reduced by oil ‘top up’


Copper Strip corrosion
IP 154 / ASTM D 130

• To evaluate corrosive properties of oil.
• Particular significance to Gear Oils



Dielectric Strength
ASTM D877 ( Up to 230 kV)
ASTM 1816 ( Higher voltages)

• Measures resistivity between two electrodes.
• Particularly for Transformer oils.
• Dielectric Strength, drops / fails due to
contamination, dust, dirt, moisture, etc..
• Also for refrigeration Oils for hermetically
sealed compressors



Foaming characteristics
IP 146 / ASTM D 892

• Generally due to contamination with surface
active materials.
• Excessively high flow rates.
• Depletion of anti foaming additive package
• May result in cavitation, pressure drop,
intermittent flow / circulation.



Pour point
IP 15 / ASTM D 97

• An indicator of the flow properties of oils at
low temperature.
• Crystallization of waxy components at low
temperature restricts the flow of oil an d
results in oil starvation.



Acidity (TAN)
IP 177:96 / ASTM D 664
• Expressed as mgKOH/gm
• Measures - total acidity of the oil i.e. presence
of strong inorganic and weak organic acids
• Increase of TAN indicates
• Hydrolysis of oil
• Oxidation
• Contamination
• High TAN values can lead to problem of
corrosion.


Water content
IP 356 (KF) / ASTM D 1744 & 4377

• Measures extend of water contamination
• In general “no water” should be present in
lubricating oil ( Max tolerated is 0.2%)
• Salt water contamination (Marine grades) may be
traced to cooler leakages, ship’s hull etc..
• Common metals in sea water include
• Sodium 11,000 ppm, Calcium 400 ppm,
• Magnesium 1,300, Potassium 400 ppm


Total insolubles
IP 316 / ASTM D 893

• Total amount of extraneous matter which are
derived from products of combustion
• Includes burnt lubricating oil and additive ash,
rust, salt, wear debris and abrasive matter. (IP
method deploys high RPM centrifuge +10,000 g, preferred for
dispersant/detergent additives lube oils- ASTM D893 is 600 – 700 g)

• Viscosity of an oil increase with increase in the
level of total insolubles.
• Expressed as % of the quantity of oil.

Common Lubricant tests - others

Additional tests commonly referred to:

• Thermal stability
• Detergency
• Dispersancy
• Anti wear Tests
• Timken OK load
• Four ball wear
• Grease consistency


Special Lubricant tests
- For used oils
Conducted on sophisticated equipment
for premium lubricants
• Elemental analysis
• Wear metal analysis (Particle size 0.1 – 1000
microns)
• ICP – Inductively Coupled Plasma Spectra photometer
• Larger, expensive to buy and maintain, good for R&D
• Atomic absorption Spectra (AAS)
• Is simpler , smaller & compact
• Ferrography (Generally larger particles 10 to 1000 micron)
• Viewed under high powered microscope, biased to Ferric,


Special Lubricant tests –
- Base oils and raw materials
Conducted on sophisticated equipment
for premium lubricants

• Fourier Transform Infra Red Spectroscopy (FITR)
• Differential Scanning Calorimeter (DSC)
• Oxidation onset Temperature (OOT)
• Gel Permeation Chromatography (GCP)
• Gas Chromatography (GC)


– Wear metal analysis – Used oils
ICP / Atomic Absorption Spectra (AAS)
Wear metals may include some of the following
• Aluminum Pistons, Bearings
• ChromiumCylinder liner, Piston rings etc..
• Copper Bearings, Coolers
• Iron Crankshaft, Gearing, Piston rings
• Lead Bearings
• Manganese Steel components
• Nickel Pistons rings, steel components
• Silver & Tin Bearings
• Molybdenum Piston rings

Elemental analysis – Used Oils
ICP / Atomic Absorption Spectra (AAS)
Elements commonly found in lubricants include
• Zinc, Phosphorus Anti wear package (ZDDP)
• Sulphur Base Oil, additives
• Sulphur Gear Oil additive
• Magnesium Rust inhibitors
• Barium Rust inhibitors
• Silicon Antifoam
• Calcium, Detergents
• Magnesium Detergents
• Boron Dispersants

Special Analytical Tests
FTIR – for Base Oils & raw material
Fourier Transform Infra red Spectroscopy

• FTIR generates a spectrum which is then used to
confirm the presence of a particular bond (Single
bond, double bond etc..)
• Used to determine paraffinic, aromatic and
naphthenic content in mineral oils
• To identify functional groups like esters, aromatics,
amide, etc..


- for Base oils and raw materials
Differential Scanning Calorimeter - DSC

• Monitoring a particular property of the oil under
isothermal conditions with time.
• Thermograms generated by this technique are
“Finger prints” of the material/ oil.
• DSC is used to determine OOT (Oxidation onset
temperature), OIT (Oxidation Induction Time and
smoke content


Oxidation onset Temperature (OOT)

• Temperature at which oxidation of the oil begins
under controlled conditions (PDSC cell)
• Characterized by peak due to heat of the reaction of
oxidation.
• Useful in deciding the working range of the oil


Gel Permeation Chromatography- GPC

• Sample passes through a column with liquid where
various components are absorbed. depending on
their molecular weight
• Used to determine molecular weight of polymers by
comparing with standard polymer of known
molecular weight


Gas Chromatography- GC

• Sample passes through a column with a carrier gas
where various components are absorbed depending
on the temperatures of the column, packing
materials etc.
• Used to determine purity and percentage of various
components present in a mixture.
• Mainly used for raw material analysis


Thank you


Testing Of Lubes And Its Significance Nov 2011

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