Lubrication -
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles. The property of reducing friction is known as lubricity (or slipperiness). In addition to industrial applications, lubricants are used for many other purposes.
Typically lubricants contain 90% base oil (most often petroleum fractions, calledmineral oils) and less than 10% additives. Vegetable oils or synthetic liquids such as hydrogenated polyolefins, esters, silicones, fluorocarbons and many others are sometimes used as base oils.
Lubrication Fundamentals -
“Lubrication Fundamentals” is intend is to be a comprehensive training material for all technical staff
within our group companies.
It will familiarize you in the wide range of high quality oils and greases, their classification and application properties.
More detailed reference data, conversion factors and common petroleum industry definitions can be
obtained from our follow-up training material “Oil Analysis and Filtration”.
Introduction :
As long as 1400 BC., the Egyptians used greases made of olive oil and lime to lubricate their wooden wagon axles.
Lubricating oils reduce friction and wear,save energy, help to reach the life expectancy of the friction
point, prevent corrosion and lower maintenance costs.
They are also used as base oils for the production of greases.
The correct lubrication with lubricating oils bears a number of advantages, as these oils carry away heat, provide cooling,help to keep abrasive particle or contamination out of the friction point and make high operating speeds possible.
Mineral Oils - Mineral Oils are divided into: Paraffinic, Naphthenic and Aromatic oils. They
account for approx. 90 % of the demand for lubricating oils.
Synthetic Oils - Synthetic oils have some characteristics that are superior to those of mineral
lubrications, at least for certain types of application. The figure shows the most important properties of some oil families.
Greases -
Greases are cohesive lubricants whose composition and product features are designed to reduce friction and wear over the widest possible temperature ranges and time spans.
The American Gear Manufacturers Association (AGMA) developed a numbering system to define gear oil viscosities required for various speed reducer types and applications. The AGMA Grades are shown below along with the equivalent ISO VG.
Calculating Grease Quantity, Frequency
Why Lubrication ?
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles. The property of reducing friction is known as lubricity (or slipperiness). In addition to industrial applications, lubricants are used for many other purposes.
Typically lubricants contain 90% base oil (most often petroleum fractions, calledmineral oils) and less than 10% additives. Vegetable oils or synthetic liquids such as hydrogenated polyolefins, esters, silicones, fluorocarbons and many others are sometimes used as base oils.
Lubrication Fundamentals -
“Lubrication Fundamentals” is intend is to be a comprehensive training material for all technical staff
within our group companies.
It will familiarize you in the wide range of high quality oils and greases, their classification and application properties.
More detailed reference data, conversion factors and common petroleum industry definitions can be
obtained from our follow-up training material “Oil Analysis and Filtration”.
Introduction :
As long as 1400 BC., the Egyptians used greases made of olive oil and lime to lubricate their wooden wagon axles.
Lubricating oils reduce friction and wear,save energy, help to reach the life expectancy of the friction
point, prevent corrosion and lower maintenance costs.
They are also used as base oils for the production of greases.
The correct lubrication with lubricating oils bears a number of advantages, as these oils carry away heat, provide cooling,help to keep abrasive particle or contamination out of the friction point and make high operating speeds possible.
Mineral Oils - Mineral Oils are divided into: Paraffinic, Naphthenic and Aromatic oils. They
account for approx. 90 % of the demand for lubricating oils.
Synthetic Oils - Synthetic oils have some characteristics that are superior to those of mineral
lubrications, at least for certain types of application. The figure shows the most important properties of some oil families.
Greases -
Greases are cohesive lubricants whose composition and product features are designed to reduce friction and wear over the widest possible temperature ranges and time spans.
THICKENER + LUBRICATING OIL + ADDITIVES
5-20% 75-95% 0-15%
Greases Characteristics :
A grease is expected to:
- Reduce friction and wear
- Provide corrosion protection
- Seal bearings from water and contaminants
- Resist leakage, dripping and throw off
- Resist change in structure or consistency during service
- Maintain mobility under conditions of application
- Be compatible with seals
- Tolerate or repel moisture
Calculating Grease Quantity, Frequency
where
Gp = grease quantity to be added when replenishing, [g]
D = bearing outside diameter, [mm]
B = total bearing width (for thrust bearings use total height H), [mm
Why Lubrication ?
Viscosity
Viscosity is the most important property of a lubricating oil. Itis a measure of the internal friction, describing the resistanceto relative motion between the molecules under sheer stress.
Viscosity depends on pressure and temperature.
It is commonly reported in centistokes (cST), measured at either 40ºC and 100 ºC due to ISO – International Organization for Standardization (kinematic viscosity).
The number in the product name for most products represents the viscosity of the oil e.g.
! Shell Omala 320 – ISO VG 320 gear oil or
! Aral Degol BG 460 – ISO VG 460 gear oil.
Operating Viscosity Application :
Operating Application
Viscosity (cSt)
10 to 22 Sewing Machines e.g. C 10
10 to 100 Hydraulics e.g. HLP 46
100 to 150 Compressors e.g. VDL 100
10 to 320 Roller Bearings e.g. CLP 68
22 to 1500 Plain Bearings e.g. CLP 220
220 to 1500 Low Speed Gears e.g. CLP 680 (Spur, Helical & Bevel)
15 to 100 High Speed Gears e.g. CLP 100
The viscosity of water is ~ 1 cSt at room temperature 20°C (68°F).
Honey might have a viscosity of ~ 2500 cSt at room temperature.
Viscosity Guide :
Viscosity Index (VI) :
Viscosity Index is a measurement of the rate of change of viscosity with temperature. This change is common to all fluids –some more, some less. Heating tends to make them thinner –cooling , thicker. The higher the VI, the less tendency for the viscosity to change.
High VI oils are often preferred for service in which a relatively constant viscosity is desired under conditions of varying temperature - e.g kiln bearings, synthetic oil with VI < 130.
The Viscosity Index is calculated from viscosities at 40°C and 100°C in accordance with the ISO or ASTM Test Method D567 or D2270.
Viscosity Index Improver :
What it Does
Reduces rate of change of viscosity with temperature
Allows an oil to be fluid at low temperatures, yet maintain thickness at high temperatures.
How it Works
The additive’s act like “popcorn”. At low temp. they are “tight – balls” which do not significantly increase the oil resistance. At high temp. these “tight-balls” explode into long chain polymers,
which increase the oils resistance to flow and thereby preventing the oil from thinning out too rapidly.
Examples
Polymethacrylates (PMA)
Olefin Copolymers (OCP)
Styrene-Isoprene (SI)
Selection and Application of Lubricating Oils -
Mineral Oils
C - DIN 51517 Part 1. Non-ageing mineral oils without additives.Primarily used for circulation lubrication.
CL – DIN 51517 Part 2. Additivated mineral oils to increase anticorrosive and anti-ageing properties. Primarily used for circulation lubrication. According to their viscosity, these oil types show good low and high temperature properties.
CLP – DIN 51517 Part 3. Additivated mineral oils to increase anticorrosive and anti-ageing resistance and to reduce wear in the mixed friction zone. Used for dip-feed and circulation lubrication, when requirements made on wear protection are extremely high.
H – Hydraulic fluids.
HL – DIN 51524 Part 1. Additivated mineral oils to improve anticorrosion
and anti-ageing properties.
HLP – DIN 51524 Part 2. Same as hydraulic oils HL plus additional additives to reduce wear due to fretting corrosion in mixed friction zones.
K – DIN 51503 (refrigerator oils). Mineral oils or oils composed of allied hydrocarbones to lubricate and cool refrigerating machine compressors.
L-TD – DIN 51515. Additivated lubricating oils with improved anticorrosion and anti-oxidation properties. To be used for the lubrication and control of steam turbines, stationary gas turbines or
machines driven by these, such as generators, compressors, pumps and gears.
VB, VC and VDL – DIN 51506. Mineral oils with or without additives for the use in air compressors with an oil lubricated pressure chamber, without injection cooling. The oil can be also used in vacuum pumps.
Z – DIN 51510. Pure mineral oils, primarily used for steam-driven sliding parts of steam engines with a steam inlet temperature less than 380 C.
Additives :
What do the additives do?
Additives are added to lubricants to positively influence the properties that the oil already has.
They add features to improve the service life, wider operating temperature range, provide rust,
foam and wear protection. They enable the oil to do things that it could not accomplish by itself.
Viscosity Index Improver
Oxidation inhibitors
Rust inhibitors
Metal deactivators
Antiwear additives
Extreme pressure additives
Friction modifiers
Detergents
Dispersants
Pour point depressants
Anti-foam agents
Tackifiers
Emulsifiers
Biocides
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2 comments
Click here for commentsI did read the whole blog and I get good information. This is a helpful blog for me. Extreme Pressure Lubricant Grease
ReplyThankyou for your blogs.It helps us alot,waiting for your next blog.We have industrial lubricants in Saudia Arabia
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