SELECTING PERFORMANCE GREASE: Ten Crucial Questions. Presented 4-13-2006 By Don Oldiges. Principles of Selection. Manufacturer recommendations
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Demands on Grease Performance
Machinery that is idle for long periods.
Moving parts that are “Sealed for Life”
Surfaces that are exposed to extreme conditions.
Extending the life of worn components.
Sealant to minimize leakage
Sealant to minimize contamination
Rigidity holds it in place where its needed
Holds finely ground solid lubricants like moly or teflon.1: Know When to Use Grease
Silicone2: Know the Types of Grease
Grease is classified by penetration number and by type of soap or other thickener.
Pour Point Depressant
Solid Boundary Lubricants
Polyalpha Olefins (PAO)
BuyerWhat is Grease?
Lithium, Sodium, Barium, Calcium, Aluminum
Clay, Graphite, Silica
Polyurea, PTFE, Wax
All greases are not created equal, caution must be exercised when replacing or refilling a grease.
C = Usually compatible.
B = Borderline compatibility (probably incompatible).
I = Incompatible
Other Metal Soaps
Al Complex 5%
Ca Complex 2%
Na Soap 2%
Ca Sulfonate 1%
Ca Anhydrous 1%
Organo Clay 3%
Ca Hydrated 10%
All Others 2%
53%What Do Most People Use?
2004 Global Production per NLGI Survey
Professional societies and organizations have established classifications for oil and grease. The most widely encountered are those of the following organizations:
MIL-G-3545High Temperature Grease
MIL-G-4343BGrease, Pneumatic System
MIL-G-7711General Purpose EP Grease
MIL-G-18458Wire Rope Grease
MIL-G-21164CGrease, Moly Disulfide
Category - H1Lubricants - General Incidental Contact
Category - H2Lubricants - General No Contact
Category - H3
Soluble Oils5: Know Any Special Requirements
Penetration with respect to a lubricating grease, is the depth (in tenths of a millimeter) that a standard cone penetrates a sample of the grease under prescribed conditions of weight, time, and temperature.
Penetration is a measure of consistency of a grease to determine its plasticity.
ASTM D-217What is Penetration?
Shear or mechanical stability of a grease is its ability to withstand repeated working with minimum change in its structure or stability.
The shearing action in the test apparatus simulates the working of the grease in service.
The consistency is measured after 60 strokes and repeated after 10,000 or more strokes.
ASTM D-217-AGrease Shear StabilityMotor-Matic Grease Worker Test
The test is the determination of the load-carrying capacity of a lubricant in kilograms applied to a system of four steel balls in the form of a tetrahedron.
The results are used to evaluate the EP characteristic of the lubricant by a load scar curve and weld point.
The procedure consists of a series of 10-second runs made at pre-selected and successively higher loads until the welding of the four balls occurs.
ASTM D-2783Four Ball EP Test
This device measures fluid viscosity at fixed rotation speeds by driving a measurement tool ("spindle"), immersed in the test fluid, through a calibrated torsion spring. Viscous drag of the fluid against the spindle causes the spring to deflect, and this deflection is correlated with torque. The calculated shear rate depends on the rotation speed, the tool geometry, and the size and shape of the sample container. Conversion factors are needed to calculate viscosity from the measured torque, and are typically pre-calibrated for specific tool and container geometries.Simple Rotational Viscometer ("Brookfield type")
Saybolt Viscosity speeds by driving a measurement tool ("spindle"), immersed in the test fluid, through a calibrated torsion spring.
Universal Seconds @ 100°F
cSt @ 40°C
Crank Case Oils
Gear OilViscosity Grade Comparisons
Drums or Totes
Performance Grease speeds by driving a measurement tool ("spindle"), immersed in the test fluid, through a calibrated torsion spring.
SUPPLIER9: Know the Marketing/Supply Channel
Where do I go to get “Good” grease?
Renewable & Safe speeds by driving a measurement tool ("spindle"), immersed in the test fluid, through a calibrated torsion spring.
Raw Materials10: Know the Life Cycle Fate