SELECTING PERFORMANCE GREASE: Ten Crucial...
Transcript of SELECTING PERFORMANCE GREASE: Ten Crucial...
Ten Crucial Questions
Principles of Selection
Manufacturer recommendations
Manufacturers usually provide a list of lubricants that meet the operating requirements for their equipment. (note that the equipment manufacturer's recommendation should not necessarily be considered the best selection.
Lubricant producer recommendations
When manufacturers recommend lubricants for their products in terms of specifications or required qualities rather than particular brand names, lubricant producers should be consulted to obtain advice on products that comply with the required specifications.
User selection
The user should follow the manufacturer's specification ensure that applicable criteria are met regardless of who makes the lubricant selection.
Ten Crucial Questions
Challenging Environments
Environmentally Friendly
Temperature Extremes
Heavy Loads
High Speeds
Long Life
Demands on Grease Performance
Ten Crucial Questions
Performance Objectives of Grease
To remain in contact with moving surfaces and
provide lubrication even under the stress of
gravity, centrifugal action or pressure.
To retain its properties under use conditions at all
levels of shear and temperature.
While performing the above, the grease must still
be able to flow or be pumped where it is needed.
Ten Crucial Questions
1: Know When to Use Grease
Applications suitable for
performance grease.
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.
Functional Properties
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.
Ten Crucial Questions
2: Know the Types of Grease
Aluminum, conventional
Aluminum, complex
Calcium, conventional
Calcium, anhydrous
Calcium, complex
Lithium, conventional
Lithium, complex
Polyurea
Organo-clay
Silicone
Grease is classified by penetration number and by
type of soap or other thickener.
Ten Crucial Questions
What is Grease?
Antioxidant
Antiwear
Antirust
Anticorrosion
Extreme pressure
VI Improver
Tackifier
Pour Point Depressant
Solid Boundary Lubricants
Dye
Petroleum Oils
Polyalpha Olefins (PAO)
Polybutenes
Esters
Polyglycols
Polyethers
Silicones
PFPE
Grease
SellerFluid LubricantBuyerAdditive SellerThickener
Soap
Lithium, Sodium,
Barium, Calcium,
Aluminum
Non-Soap (inorganic)
Clay, Graphite, Silica
Carbon Black
Non-Soap (organic)
Polyurea, PTFE, Wax
Ten Crucial Questions
Grease Compatibility Chart
Alu
min
um
Co
mp
lex
Bariu
m
Calc
ium
Calc
ium
-Hyd
rox
y
Calc
ium
Co
mp
lex
Cla
y
Lith
ium
Lith
ium
-Hyd
rox
y
Lith
ium
Co
mp
lex
Po
lyu
rea
Aluminum Complex C I I C I I B B C B
Barium I C I C I I I I I I
Calcium I I C C I C C B C I
Calcium 12-Hydroxy C C C C C C C C C I
Calcium Complex I I I B C I I I C C
Clay I I C C I C I I I I
Lithium B I C C I I C C C I
Lithium 12-Hydroxy B I B C I I C C C I
Lithium Complex C I C C C I C C C I
Polyurea B I I I C I I I I C
C = Usually compatible.
B = Borderline compatibility (probably incompatible).
I = Incompatible
12
12
All greases are not created equal, caution must be
exercised when replacing or refilling a grease.
Ten Crucial Questions
What Do Most People Use?
2004 Global Production per NLGI Survey
Li Conventional
53%
Li Complex
15%
Ten Crucial Questions
3: Know your Classifications
SAE (Society of Automotive Engineers)
API (American Petroleum Institute)
AGMA (American Gear Manufacturers
Association),
ISO (International Standards Organization)
NLGI (National Lubricating Grease Institute).
Professional societies and organizations have established
classifications for oil and grease. The most widely
encountered are those of the following organizations:
Ten Crucial Questions
NLGI grease classification
NLGI
Number
ASTM Worked
Penetration
Consistency
000 445 - 475 Semi-fluid (Ketchup)
00 400 - 430 Semi-fluid (Applesauce)
0 355 – 385 Very soft (Deli Mustard)
1 310 – 340 Soft (Tomato Paste)
2 265 – 295 Common Grease (Peanut Butter)
3 220 – 250 Semi-hard (Solid Shortening)
4 175 – 205 Hard (Frozen Yogurt)
5 130 – 160 Very Hard (Hard Butter)
6 85 - 115 Solid (Brick Cheddar Cheese)
Ten Crucial Questions
4: Know the Typical Performance
Properties of Each type of Grease
Ma
x U
sa
ble
Te
mp
°F
Th
erm
al
Sta
bility
Lu
bric
ity
Wa
ter
Res
ista
nc
e
Sa
lt Wa
ter
Res
ista
nc
e
Sh
ea
r Sta
bility
Ox
ida
tion
Sta
bility
Ru
st
Pro
tec
tion
Pu
mp
ab
ility
Oil S
ep
ara
tion
Aluminum, conventional 175
Aluminum, complex 350
Calcium, conventional 200
Calcium, anhydrous 230
Calcium, complex 350
Lithium, conventional 275
Lithium, complex 350
Polyurea 350
Organo-clay 350
Sodium 350
Excellent Good Fair Poor
Ten Crucial Questions
5: Know Any Special Requirements
Special Performance
Requirements
Federal Specs and
Standards
Mil Specs and
Standards
Food Grade
Specifications
ISO Standards
ASTM Specifications
EXAMPLES
MIL-G-3545
High Temperature Grease
MIL-G-4343B
Grease, Pneumatic System
MIL-G-7711
General Purpose EP Grease
MIL-G-18458
Wire Rope Grease
MIL-G-21164C
Grease, Moly Disulfide
MIL-G-25760
Synthetic Grease
MIL-G-46886
Silicone Grease
EXAMPLES
Category - H1
Lubricants - General
Incidental Contact
Category - H2
Lubricants - General No
Contact
Category - H3
Soluble Oils
Ten Crucial Questions
6: Know the Grease Characteristics
Required for the Application
Apparent Viscosity (non-Newtonian)
Bleeding, Migration, Oil Separation
Consistency, Penetration, NLGI Numbers
Corrosion, Rust and Water Resistance
Dropping Point
Evaporation
Oxidation Stability
Pumpability
Shear Stability
Temperature effects
Pressure Effects
Ten Crucial Questions
Typical Grease Tests
Test ASTM
Method
Test Description
Cone Penetration D-217 Depth a “cone” pushes into grease
Dropping Point D-2265 Temperature where grease “melts”
Apparent Viscosity D-1092 “Thickness” of grease
4 Ball Wear D-2266 Apply load until balls weld
Evaporation D-972 Weight loss from grease
Copper Corrosion D-4048 Chemical reactivity with metal
Water Washout D-1264 Removal of grease by water
Rust Resistance D-1743 Protection of iron & steels
Oxidation Stability D-942 Storage stability
Ten Crucial Questions
What is Penetration?
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-217
Ten Crucial Questions
Grease Shear Stability
Motor-Matic Grease Worker TestShear 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-A
Ten Crucial Questions
Four Ball EP 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-2783
Ten Crucial Questions
Simple Rotational Viscometer
("Brookfield type") 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. Viscousdrag 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.
Ten Crucial Questions
Viscosity Grade ComparisonsKinematic Viscosity
cSt @ 40°C
Saybolt Viscosity
Universal Seconds @ 100°F
ISO/ASTM
Viscosity
AGMA
Grades
SAE
Crank Case Oils
SAE
Gear Oil
10,000
5,000
3,000
2,000
1,000
500
300
200
100
60
1,000
500
300
200
100
50
30
20
10
2,000
Ten Crucial Questions
7: Know how the Grease is Applied
Automatic lubricating systems
Pressure Injectors
Metering pump
Hand operated grease applicator
Cartridge Grease Gun
Grease Filler Pump
Brush
Ten Crucial Questions
8: Know the Packaging Required &
Available
Aerosols
CartridgesSmall Containers
Pails
Drums or Totes
Ten Crucial Questions
9: Know the Marketing/Supply Channel
SUPPLIER
Performance Grease
GREASE
MAKER
PRIVATE
LABELERDISTRIBUTOR
CO-OP/
BUYING
GROUP
Where do I go to get “Good” grease?
Ten Crucial Questions
Performance
Grease
10: Know the Life Cycle Fate
Packaged Grease
Distribution Warehouse
Consumer
Disposal
Raw Materials
Environmentally
Responsible
Renewable & Safe