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SELECTING PERFORMANCE

GREASE:

Ten Crucial QuestionsPresented

4-13-2006

By

Don Oldiges

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.


Challenging Environments

Environmentally Friendly

Temperature Extremes

Heavy Loads

High Speeds

Long Life

Demands on Grease Performance


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.


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.


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.


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


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.


What Do Most People Use?

2004 Global Production per NLGI Survey

Li Conventional

53%

Li Complex

15%


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:


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)


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


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


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


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


Common Test EquipmentPenetrometer Grease Worker


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


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


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


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.


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


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


Example of a Large Automatic Lube

Application System


8: Know the Packaging Required &

Available

Aerosols

CartridgesSmall Containers

Pails

Drums or Totes


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?


Performance

Grease

10: Know the Life Cycle Fate

Packaged Grease

Distribution Warehouse

Consumer

Disposal

Raw Materials

Environmentally

Responsible

Renewable & Safe


QUESTIONS???



Anhydrous Calcium Grease


Bentonite Clay Grease


Calcium Complex Grease


Lithium Complex Grease


Lithium 12-Hydroxy Grease


Aluminum Complex Grease


Silicone Grease


Fluorosilicone Grease


Polyurea Grease


Fatty Acids for Grease


Grease Reactions


Trimer Reaction


PAO 4


PAO 40


ExxonMobil Synthetic Oils

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