© 2003 The Lubrizol Corporation
Grease ApplicationsWhen to Lubricate with a Grease
• To reduce lubricant leakage, dripping and spattering• To reduce relubrication frequency• To help seal out contaminants• For equipment that runs intermittently or is kept in storage for
long time periods• For extreme operating conditions (high temperatures,
pressures, shock loads, low speeds)• For badly worn equipment (thicker grease films work well in
worn, increased clearances)• For noise reduction in badly worn equipment (grease acts as a
"cushion")• To suspend (act as a reservoir for) solid additives
GR101-002
© 2003 The Lubrizol Corporation
Grease ApplicationsGrease Requirements
• High speed• Temperature extremes• Water tolerance• Corrosion protection• Pumpability• Oxidation inhibition• Impact, shock loading
GR101-008
© 2003 The Lubrizol Corporation
Grease Applications
GR101-011
Thickener StructureDropping Point
°F/°CMax Service
Temperature °F/°C
Sodium soap Fibrous 350/177 200-275/93-136
Calcium soap simple Smooth 270-290/132-143 250/121
Complex Smooth, buttery >450/>232 300/149
Lithium soap simple Smooth 390/199 325/163
Complex Smooth, slightly stringy >450/>232 350/177
Aluminum complex Smooth gel >450/>232 300/149
Clay Smooth >500/>260 350/177
Polyurea Opaque, slightly mealy >450/>232 350/177
© 2003 The Lubrizol Corporation
Grease ApplicationsSoap Thickened Greases
GR101-012
Type Thickener Characteristics Applications
Aluminum Smooth, gel-like appearanceLow dropping pointExcellent water resistanceSoftening/hardening tendenciesGreatly dependent on shear rate
Lubricate low speed bearingsWet applicationsUsage decreasing
Sodium Rough, fibrous appearanceModerately high dropping pointPoor water resistanceGood adhesive (cohesive) properties
Older industrial equipmentWhere relubrication is frequentRolling contact bearing
Calcium Smooth, buttery appearanceLow dropping pointsGood water resistance
Bearings in wet applicationsRailroad rail lubricant
Lithium Smooth, buttery to slightlyStringy appearanceHigh dropping pointResistant to softening and leakageModerate water resistance
Automotive chassis and wheel bearingsGeneral industrial greaseThread lubricants for oil drilling industry
© 2003 The Lubrizol Corporation
Grease ApplicationsComplex Soap Thickened Greases
GR101-013
Type Thickener Characteristics ApplicationsAluminum complex Smooth, slight gel-like
appearanceDropping points above 450°FGood water resistanceShorter life at high temperature
Steel mill roll neckRolling and plain bearings
Calcium complex Smooth, buttery appearanceDropping points above 450°FGood water resistanceInherent EP/load-carrying capability
High-temperature industrial and automotive bearing applications
Lithium complex Smooth, buttery appearanceDropping points above 450°FResistant to softening and leakageModerate water resistance
Automotive wheel bearingHigh-temperature industrial service including various roller-element applications
© 2003 The Lubrizol Corporation
Grease ApplicationsOther Thickened Greases
GR101-014
Type Thickener Characteristics Applications
Polyurea Smooth, slight opaque appearanceDropping points above 450°FGood water resistanceOxidation resistantLess resistant to softening and leakage
Industrial roller-element bearingsAutomotive constantVelocity joints
Organo-clay Smooth, buttery appearanceDropping point above 500°FResistant to leakageGood water resistance
High temperature bearings with frequent relubricationSteel mill roll neckSteel mill roll neck bearings
© 2003 The Lubrizol Corporation
Grease ApplicationsWhen to Lubricate with a Grease
• Choice depends on:− Expected operating conditions− Lubrication system to be used− Properties of available lubricants
• Greases are frequently used to lubricate machine parts which are difficult to reach during operation
• Greases are especially suitable for severe or extreme operating conditions:− High operating temperatures− Heavy or shock loading− Low speed with high pressure− Intermittent operation
GR101-015
© 2003 The Lubrizol Corporation
Grease ApplicationsOil versus Grease for Bearings - Advantages
GR101-016
Oil Grease
Excellent heat transfer Simplifies seal designActs as a sealant
Carries away dirt and moisture
Permits prepacking of bearings
Easily controlled lubrication
Requires less frequent lubrication
© 2003 The Lubrizol Corporation
Grease ApplicationsCompatibility Chart
10-20-97 GR101-075
AluminumComplex Barium Calcium
Calcium12-Hydroxy
CalciumComplex Bentone Lithium
Lithium 12-Hydroxy
Lithium Complex Polyurea
AluminumComplex I I C I I I I C I
Barium I I C I I I I I I
Calcium I I C I C C B C I
Calcium12-Hydroxy C C C B C C C C I
CalciumComplex I I I B I I I C C
Bentone I I C C I I I I I
Lithium I I C C I I C C I
Lithium 12-Hydroxy I I B C I I C C I
Lithium Complex C I C C C I C C I
Polyurea I I I I C I I I I
B = Borderline compabilityC = CompatibleI = Incompatible
© 2003 The Lubrizol Corporation
Grease ApplicationsReading the Specification Sheet
• Read worked penetration (P60)− Determine grade
• Read dropping point− Estimate heat resistance
• Read base oil viscosity− Estimate suitability for high or low speed application− Estimate suitability for high or low load application− Estimate pumpability
• Read thickener type− Estimate water resistance− Estimate pumpability
01-27-98 GR101-076
Fluid technologies for a better world™
© 2004 The Lubrizol Corporation
Function and Chemical Composition
01-30-04 GR103-001
© 2003 The Lubrizol Corporation
Function and Chemical CompositionNLGI Definition
GR103-004
Grease:
“A solid to semisolid product of dispersion of a thickening agent in a liquid lubricant. Additives imparting special properties may be included.”
© 2003 The Lubrizol Corporation
Function and Chemical Composition
Base Stock86%
Performance Additive
4%
Thickener10%
10-20-97 GR103-005
© 2003 The Lubrizol Corporation
Function and Chemical CompositionProperties Contributed by Thickeners
GR103-011
Thickener TypeShear
StabilityWater
ResistanceHigh Temperature
Stability
Calcium (Hydrous) M G P (90)
Calcium (Anhydrous) G G M (140)
Lithium G M G (180)
Sodium M-G P G (200)
Calcium Complex M G G (300)
Lithium Complex G M-G G (250)
Polyurea M-G G G (240)
Bentonite Clay M M G (None)G = Good, M = Medium, P = Poor( ): Dropping Point °C
© 2003 The Lubrizol Corporation
Function and Chemical CompositionProperties Determined by Thickener Alone
• Rheology• Water resistance
GR103-012
© 2003 The Lubrizol Corporation
Function and Chemical CompositionRheology
• Describes behavior of flowing materials under stress• Shear rate
− Rate at which adjacent layers of a substance move against one another
• Shear stress− Force which must be applied to a substance in
order to cause shear
GR103-013
© 2003 The Lubrizol Corporation
Function and Chemical CompositionGrease Properties Determined by Base Fluid Alone• Evaporation loss
GR103-018
© 2003 The Lubrizol Corporation
Function and Chemical CompositionGrease Properties Determined Jointly by Thickener, Base Fluid, and Additives• Consistency• Oxidative and thermal stability• Corrosion resistance• Structure stability• Load carrying capability• Low temperature behavior• Dropping point• Elastomer compatibility
GR103-019
© 2003 The Lubrizol Corporation
Function and Chemical CompositionThickener
• Solvency of fluid medium in thickener• Solvency of thickener in the fluid medium• Attractive forces between the thickener and the fluid• Capillary forces holding the fluid within the fiber
network• Mechanical interlocking of the fiber network
12-10-96 GR103-029
© 2003 The Lubrizol Corporation
Function and Chemical CompositionNaphthenic Base Oils
• Soap tends to be smoother• Soap is more translucent• Oil has better affinity for soap• Pour point lower• Low temperature pumpability
12-10-96 GR103-030
© 2003 The Lubrizol Corporation
Function and Chemical CompositionParaffinic Base Oils
• High temperature stability• Improved oxidation resistance• Soap formation more difficult• Higher soap content
12-10-96 GR103-031
© 2003 The Lubrizol Corporation
Function and Chemical CompositionSynthetic Base Oils
• Performance at high and low temperatures• Specialty applications• Soap formation difficult• Soap content high
12-10-96 GR103-032
© 2003 The Lubrizol Corporation
Function and Chemical CompositionVegetable Base Oils
• Biodegradability• Oxidation during heating cycle• Low temperature mobility• High temperature performance• Soap content high
12-10-96 GR103-033
© 2003 The Lubrizol Corporation
Performance Additives for Grease
• Grease additives may be− Organic
• Chemically activeOr
• Chemically inert− Solid lubricants (inorganic)
GR105-00203-29-05
© 2003 The Lubrizol Corporation
Performance Additives for GreaseChemically Inert Additives
• Affect a physical property such as structure, rheology, or water tolerance
GR105-003
© 2003 The Lubrizol Corporation
Performance Additives for GreaseExamples of Chemically Inert Additives
• Viscosity modifiers• Pour Point depressants• Antifoam agents• Emulsifiers• Demulsifiers
GR105-004
© 2003 The Lubrizol Corporation
Performance Additives for GreaseChemically Active Additives
• Produce their effect through chemical reaction either within the lubricant medium or on the metallic surface
GR105-005
© 2003 The Lubrizol Corporation
Performance Additives for GreaseExamples of Chemically Active Additives
• Oxidation inhibitors• Rust and corrosion inhibitors• EP/antiwear agents
GR105-006
© 2003 The Lubrizol Corporation
Performance Additives for GreaseCurrent Chemistry
• Antimony dithiocarbamate• Sulfurized olefin (combinations)• Chlorinated compounds• Barium sulfonate• Lead dithiocarbamate• Zinc dithiophosphates
GR105-011
© 2003 The Lubrizol Corporation
Performance Additives for GreaseFuture Chemistry
• No lead• No antimony• No zinc• No barium• No chlorine• No sodium nitrite
GR105-012
© 2003 The Lubrizol Corporation
Performance Additives for GreaseFactors Influencing Additive Selection
• Performance requirements− Product application
• Compatibility− Synergistic/antagonistic reactions
• Environmental considerations− Product application− Odor− Disposal− Biodegradability
• Color• Cost
GR105-015
© 2003 The Lubrizol Corporation
Performance Additives for GreaseTypes of EP Agents Used in Grease Formulations• Ashless dithiocarbamates• Borates• Calcium acetate• Chlorinated paraffins• Lead naphthenates and carboxylates• Metal dithiocarbamates• Phosphate and thiophosphate esters• Sulfurized olefins and esters• Zinc dialkyldithiophosphates
04-01-98 GR105-018
© 2003 The Lubrizol Corporation
Performance Additives for GreaseAntiwear Agents
• Borates• Metallic dialkyldithiophosphates• Phosphate and thiophosphate esters• Various molybdenum compounds
04-01-98 GR105-019
© 2003 The Lubrizol Corporation
Performance Additives for GreaseZinc Dialkyl Dithiophosphates
GR105-020
Antiwear AntioxidantHydrolytic Stability
Thermal Stability
Aromatic Poor Poor Poor Best
Primary Moderate Moderate Moderate Moderate
Secondary Best Best Best Poor
© 2003 The Lubrizol Corporation
Performance Additives for GreaseOxidation Resistance Factors
• Type of thickener• Relative acidity or basicity• Nature of base oil component
GR105-023
© 2003 The Lubrizol Corporation
Performance Additives for GreaseResults of Oxidation
• Increase in penetration• Lowering of dropping point• Drying and cracking• Increased uptake of oxygen• Increased acid number• Deposits on bearing surfaces
GR105-024
© 2003 The Lubrizol Corporation
Performance Additives for GreaseTypes of Oxidation Inhibitors
• Hindered phenols• Aromatic amines• Heterocyclic nitrogen compounds• Metal dialkyldithiophosphates• Metal dialkyldithiocarbamates
GR105-025
© 2003 The Lubrizol Corporation
Performance Additives for GreaseOxidation Inhibitors
• Aromatic amines− Effective at high temperatures; offer little inhibition
at low temperatures• Alkylated phenols
− Function well at low temperatures; less effective at high temperatures because of volatility
• Metal dithiocarbamates− Effective oxidation inhibitors because of their
ability to scavenge hydroperoxides− Dual functionality as oxidation inhibitors and EP
agents
GR105-026
© 2003 The Lubrizol Corporation
Performance Additives for GreaseRust Inhibitors
• Usually highly polar oil soluble compounds• Function by adsorption on metal surface to form
protective film• Function by adsorption on metal surface• Form thin protective film which excludes air and
moisture
GR105-027
© 2003 The Lubrizol Corporation
Performance Additives for GreaseTypes of Rust Inhibitors
• Fatty amines• Fatty amides• Carboxylic acids• Sodium and calcium sulfonates• Barium sulfonates• Sodium nitrite
GR105-028
© 2003 The Lubrizol Corporation
Performance Additives for GreaseMetal Deactivators Triazole and Thiazole Derivatives• Passivate nonferrous metal surfaces• Compete with sulfur for metal surface to prevent
formation of dark sulfide stains
GR105-029
© 2003 The Lubrizol Corporation
Performance Additives for GreaseTackiness Agents
Impart surface adhesion• Polymers• Polyisobutylene• Polymethacrylate• OCP (olefin copolymer)• Styrene/diene copolymers
GR105-03007-12-05
© 2003 The Lubrizol Corporation
Performance Additives for GreaseSolid Additives - Function
• May impart durability as well as EP protection• Most useful in protecting heavily loaded bearings
from fretting wear galling and seizing• Function at the metal surface under boundary
conditions• Provide method for product recognition
GR105-031
© 2003 The Lubrizol Corporation
Performance Additives for GreaseSolid Additives - Example
• Molybdenum disulfide• Graphite• Powdered zinc• Zinc oxide• Titanium dioxide• Cerium fluoride
01-27-98 GR105-032
© 2003 The Lubrizol Corporation
Performance Additives for GreaseMultipurpose EP Grease: Typical Additive Package
GR105-034
%
Extreme pressure 2.00Friction modifier 0.50Antiwear agent 0.50Rust inhibitor 0.50Oxidation inhibitor 0.25Metal deactivator 0.25Total 4.00
© 2003 The Lubrizol Corporation
Performance Additives for GreaseMultipurpose EP Grease: Typical Performance
06-05-05 GR105-035
Additive
Test Method No Yes
Timken OK load D 2509 8 lb. 45 lb.
Four ball wear D 2266 .68 mm .45 mm
Four ball EP D 2596
LWIWeld
20.0160 kg
50315 kg
Rust D 1743 Fail Pass
Oxidation D 942 --- <5.0 psi Lossat 100 hrs.
Copper corrosion D 4048 1A 1B
Top Related