Grease product knowledge
-
Upload
rajiv-ranjan -
Category
Automotive
-
view
294 -
download
0
Transcript of Grease product knowledge
Greases
Product Knowledge
Presented by : RAJIV RANJAN
Presented by : RAJIV RANJAN
What is a grease ?
A solid to semi-fluid product
consisting of a fluid lubricant and a
thickener
It usually contains additives to
enhance performance
Typical grease contents
oil 80-87%
thickener 8-15%
additives 5%
Oil
Thickener
Additives
Presented by : RAJIV RANJAN
Lubricating greases vs. Oils
Oils
Fluid
Run away
remove heat (cool)
remove debris (clean)
remove particles
(clean)
Classification
Viscosity (SAE)
Greases
Semi-fluid / semi-solid
Stay in place
Seal
no cooling / no
cleaning
Classification
Consistency (NLGI)
Presented by : RAJIV RANJAN
When to lubricate with grease ?
• To decrease dripping and splattering of lubricant
• To decrease frequency of lubrication
• To seal out contaminants
• For intermittent operation
• To suspend solid additives
• Under extreme operating conditions • high temperature
• high pressure
• shock loading
• slow speed / high pressure
• Machine badly worn
• When noise reduction is very important
Presented by : RAJIV RANJAN
How grease works ?
• Consider Grease as a Sponge
• 3-D network of thickener particles
• Thickener particles adhere to each other due to chemical attractive forces
• Pores filled with oil/additives
Presented by : RAJIV RANJAN
GRADE
NUMBER STRUCTURE
PENETRATION
(WORKED) mm/10
CONE SINKING
DEPTH
SEMI FLUID
SEMI FLUID
VERY SOFT
SOFT
MEDIUM SOFT
MEDIUM
STIFF
VERY STIFF
VERY STIFF
445 - 475
400 - 430
355 - 385
310 - 340
265 - 295
220 - 250
175 - 205
130 - 160
85 - 115
000
00
0
1
2
3
4
5
6
NLGI number
Presented by : RAJIV RANJAN
Rolling Element Bearings
Ball bearing
General purpose bearings
Cylindrical roller bearing
Wheel bearings on cars
Bearings on gearboxes
Taper Roller Bearing
Wheel bearings on trucks & LCVs
Presented by : RAJIV RANJAN
Wheel Bearing Lubrication
Two basic types
Oil Lubricated
Grease Lubricated
Grease-Lubricated Wheel Bearings
HCV Hub-Cut section Taper roller bearings
Presented by : RAJIV RANJAN
CHASSIS GREASE
Pumpability
Good water resistance
“Stay put” anti-squeeze property
Anti-rust properties
Cost
Grease nipple
Presented by : RAJIV RANJAN
Grease formulation
Grease = Base oils + Thickeners +
Additives
The thickeners most used in grease
production:
Metal soaps (Li, Ca, Na)
Metal complex soaps (Li, Ca, Al)
Inorganic thickeners (bentonites,
silicates)
Others (polymers, polyurea)
Presented by : RAJIV RANJAN
Additives in greases
Antiwear
EP additives
Antioxidants
Tackiness agents
Corrosion inhibitors
Compatibility with thickener systems is
of prime importance
Presented by : RAJIV RANJAN
Anti-Wear Additives
Zinc based
Presented by : RAJIV RANJAN
Extreme Pressure (EP) Additives
Sulfur-Phosphorus Compounds (S-P)
Presented by : RAJIV RANJAN
Other Additives
Anti oxidants
Reduce ill effects of oxidation
Tackifiers
Improve adherence
Corrosion inhibitors
Presented by : RAJIV RANJAN
How is grease produced ?
Re
ac
tor
(Pre
ss
uri
sed
)
Homogenisation
(milling)
& Deaeration
Base
Oil
(Major portion) Fatty
Acids Alkali
Fin
ish
ing
Ke
ttle
Base
Oil
(Minor portion) Additives
Heating/cooling
jacket
Filling
Hot
Oil
Presented by : RAJIV RANJAN
Performance testing
Penetration
Mechanical stability
Oil separation
Drop point
Water resistance
Extreme pressure
performance
Four Ball weld load test
Presented by : RAJIV RANJAN
PENETRATION
Penetration is the depth, in tenths of millimeters, to which a standard cone sinks into the grease under prescribed conditions.
Presented by : RAJIV RANJAN
Penetration Contd...
Presented by : RAJIV RANJAN
Worked Penetration
Worked to X strokes
X – 10,000
Presented by : RAJIV RANJAN
Drop Point
• Determines the temperature at which a soap thickened grease passes from solid to a semi-solid state.
• Measured in deg C
Presented by : RAJIV RANJAN
Drop Point contd ….
Presented by : RAJIV RANJAN
SIGNIFICANCE
Directional change in consistency while in service
Measure of shear stability
50 gm grease in a tube with 5 Kg weight and rotated
2 hrs, 20-35 deg C
Low shear
MEASURED AS
Change in cone penetration value (in %)before & after test
Roll stability
Presented by : RAJIV RANJAN
Heat stability -Oil Separation (Conical Sieve) Method)
SIGNIFICANCE
Co-relates with oil separation in storage
100 deg C, 30 hrs
MEASURED AS
Loss of oil mass
Presented by : RAJIV RANJAN
Copper Corrosion ASTM
Temperature 100°C
Duration 24 h
Copper strip in a tube with grease ,compare with the
standard
Presented by : RAJIV RANJAN
Wheel Bearing grease leakage test
SIGNIFICANCE
Measures leakage tendency of grease
CONDITION
Wheel-hub assembly under rotation
660 rpm, 6 hrs
113 Deg C
MEASURED AS
Mass of grease + oil leaked out in gms
Presented by : RAJIV RANJAN
Resistance to water washout Test
SIGNIFICANCE
Resistance of the grease to getting washed out by water
CONDITION
600 rpm
Water impinge at 5 ml/sec
1 hr
MEASURED AS
Grease mass loss (%)
Presented by : RAJIV RANJAN
Emcor Rust Test
SEVERE TEST
10gm grease+20ml water
3 days run
108 hrs stop
SIGNIFICANCE
Corrosion prevention in the presence of distilled water
MEASURED AS
Visual rating system for pass / fail
No. of rust spots
Presented by : RAJIV RANJAN
Results
No corrosion – 0 Rating
Traces – 1 Rating (<3 Spots)
Light – 2 Rating (< 1%)
Moderate – 3 Rating (1-5%)
Heavy – 4 Rating (5-10%)
Severe – 5 Rating (>10%)
Emcor Rust Test Contd...
Presented by : RAJIV RANJAN
Extreme Pressure & Anti-wear Properties
4 ball weld load test
Wear Scar Dia
Presented by : RAJIV RANJAN
Key selling points -
• Superior shock load protection and Better anti-wear performance
• Superior corrosion protection
• Better lubricity
• Excellent resistance to water washout
• Superior control on oil bleeding under operation
• Superior heat stability
• Extremely high structural strength
• Lower leakage tendency under storage
• Longer life
Presented by : RAJIV RANJAN
STORAGE AND HANDLING
Storage of barrels-Inside storage ideal
Grease surface in barrels to be convex
Contamination
Water
Solids
Other Lubricants
Dust – the largest enemy of grease
Presented by : RAJIV RANJAN
Market Practices
• Poor quality hub grease
• Frequent breakdown
• Bearing failure
• Frequent re greasing
• Used grease/’Batata Grease’ for chassis greasing