testing of lubes and its significance nov 2011
DESCRIPTION
Typical tests carried out on lubricantsTRANSCRIPT
Testing of lubricants & its significance
Type of lubricantsAutomotive LubricantsIndustrial lubricants
Hussam Adeni [email protected]
Testing of lubricants & its significance
Automotive Lubricants• Engine Oils• Gear Oils• Brake Fluids• Coolants• Automatic Transmission Fluid
Hussam Adeni [email protected]
Testing of lubricants & its significance
Industrial Lubricants• Metal working Oils
• Neat, Soluble, Synthetic,• Semi synthetic• Metal Deformation• Heat Treatment
• Corrosion Preventives• Dewatering Fluids
• Industrial Cleaners• Compressor Oils
Hussam Adeni [email protected]
Testing of lubricants & its significance
Industrial Lubricants• Hydraulic Fluids• Industrial Gear Oils• Turbine Oils• Refrigeration Oils• Greases• Rock Drill Oils• Electrical Oils• Process Oils• Ginning Oils
Hussam Adeni [email protected]
Routine Lubricant tests
Gear Oils
• Color• Condition / Appearance• Acidity• Water content• Wear Metal Analysis (for used Oils)
Hussam Adeni [email protected]
Routine Lubricant tests
Turbine Oils
• Color• Condition Appearance• Acidity• Water content• Kinematic Viscosity at 40 °C• Demulsification value• Wear Metal Analysis (for used Oils)
Hussam Adeni [email protected]
Routine Lubricant tests
Compressor Oils
• Color• Condition Appearance• Acidity• Water content• Kinematic Viscosity at 40 °C• Wear Metal Analysis (for used Oils)
Hussam Adeni [email protected]
Routine Lubricant tests
Refrigeration Oils
• Color• Pour /Floc point• Dielectric strength• Acidity• Water content• Kinematic Viscosity at 40 °C• Wear Metal Analysis (for used Oils)
Hussam Adeni [email protected]
Common Lubricant tests
Appearance
• Fresh Oil is bright and clear• Presence of water or other contaminants make
the oil hazy / cloudy
Hussam Adeni [email protected]
Common Lubricant tests
DensityIP 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
Hussam Adeni [email protected]
Common Lubricant tests
ColourASTM 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
Hussam Adeni [email protected]
Common Lubricant tests
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°CHussam Adeni [email protected]
Common Lubricant tests
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)
Hussam Adeni [email protected]
Common Lubricant tests
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
Hussam Adeni [email protected]
Common Lubricant tests
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’Hussam Adeni [email protected]
Common Lubricant tests
Copper Strip corrosionIP 154 / ASTM D 130
• To evaluate corrosive properties of oil.• Particular significance to Gear Oils
Hussam Adeni [email protected]
Common Lubricant tests
Dielectric StrengthASTM 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
Hussam Adeni [email protected]
Common Lubricant tests
Foaming characteristicsIP 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.
Hussam Adeni [email protected]
Common Lubricant tests
Pour pointIP 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.
Hussam Adeni [email protected]
Common Lubricant tests
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.
Hussam Adeni [email protected]
Common Lubricant tests
Water contentIP 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
Hussam Adeni [email protected]
Common Lubricant tests
Total insolublesIP 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.Hussam Adeni [email protected]
Common Lubricant tests - others
Additional tests commonly referred to:
• Thermal stability• Detergency• Dispersancy• Anti wear Tests
• Timken OK load• Four ball wear
• Grease consistency
Hussam Adeni [email protected]
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,
Hussam Adeni [email protected]
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)
Hussam Adeni [email protected]
Special Lubricant tests – 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
Hussam Adeni [email protected]
Special Lubricant tests 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
Hussam Adeni [email protected]
Special Analytical TestsFTIR – 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..
Hussam Adeni [email protected]
Special Analytical Tests- 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
Hussam Adeni [email protected]
Special Analytical Tests- for Base oils and raw materials
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
Hussam Adeni [email protected]
Special Analytical Tests- for Base oils and raw materials
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
Hussam Adeni [email protected]
Special Analytical Tests- for Base oils and raw materials
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
Hussam Adeni [email protected]