Sodium Soap Grease Definition
Sodium Soap Grease, which is very similar to domestic soap used for washing, were found to have higher melting points than calcium soaps. Greases based on sodium soaps were fundamental in the lubrication of steam engines and the early machinery of the industrial revolution. Sodium grease has an operating capability up to temperatures of approximately 110ºC and it became the foremost high temperature grease at the beginning of the 20th century. Unfortunately sodium greases have three significant weaknesses. They are water soluble like washing soap and also suffer from hardening in storage. Furthermore, due to the large fibre size of traditional sodium soaps, they do not contribute lubricity to the grease. This inadequacy results in poorer load carrying capabilities and means that a base oil of higher viscosity is needed to provide heavy duty properties. The use of sodium grease is declining rapidly, but occasional applications are still found in enclosed gears and couplings.
Sodium Soap Grease Applications
- Used mainly in automotive wheel bearings.
- Used in Chassis.
- Used in Axle joints.
- Used in Low-load.
- Used in Normal/low-speed bearings.
- Can be mixed with other greases to produce higher quality grease.
- High dropping points (typically 175°C).
- Operated at 121°C.
- Poor oxidative stability.
- High oil bleed.
- Poor water Resistance.
- Good shear stability and lubricity.
- Suffer from hardening in storage.
- Excellent protection against rust.
- High Temperature Strength: It is resistant to runoff, rust and oxidation at high temperatures.
- Protection Against Dust: Due to its fibrous structure, it effectively protects the equipment against dusty contaminants.
- Economic Lubrication: For medium and high speed, low-running bearings, provide the most economical and efficient lubrication.
- Superior Protection Performance: It protects the bearings due to the natural rust protection against rust.
|DRIPPING POINT , °C (LEAST)
|ASTM D 556
|WORKED PENETRATION, 25°C, 60 IMPACT
|ASTM D 92
Lithium Grease Definition
Lithium Grease is primarily used as components of certain lubricant greases. Put simply, the oil is the main dynamic lubricator; the thickener determines the physical characteristics of the product; and additives enhance the operating properties of the grease. Lithium is a type of thickener; so not only provides structure to hold the oil in place, but it also acts as a sponge by releasing small amounts of oil during operation. There are several different types of thickener depending on application requirements and factors; such as moisture levels, extremes of temperature and speed. However, for many applications that are deemed non-extreme or general purpose in nature.
Extreme Pressure Lithium Grease
EP LITHIUM GREASE is multi-purpose extreme pressure grease made from lithium soap stock which imparts good high and low temperature characteristics and chemical stability. The load carrying additives system contains no lead or metals which are environmentally undesirable.
WHITE LITHIUM GREASE
WHITE LITHIUM GREASE is a creamy-white lubricant made with high quality base oil, lithium soap and non-abrasive basic oxides. Mild EP anti-wear additives provide additional protection and longer bearing life. It has excellent pumpability characteristics, good shear stability, and does not harden or soften readily under moderately high temperature.
Lithium Grease Applications
- Used in lubrication of heavily loaded plain and antifriction bearings, gears…(More Info) and grease lubricated couplings subject to high temperatures and shock loading. Lithium Grease is a true multi purpose grease, formulated for lubrication of loaded slide-, ball-, and roller-bearings, wheel bearings, universal joints, chassis, and various shock loaded or vibrating applications in transport, agriculture and off road equipment, operating in wet, dusty and/or dry conditions.
- Recommended for all types automotive and industrial applications including the lubrication of heavy construction equipment
- Recommended for all types of bearings including plain bearings, heavily loaded journal bearings, ball and roller bearings, needle bearings and couplings
- Recommended for wheel bearings, including disc brake application, fifth wheels, U-joints, steering linkage and chassis applications
- For use in electric motors of the NEMA insulation class A and B types
- Excellent Grease for most “sealed-for-life” bearings
- Suitable as general purpose grease for industrial applications requiring a NLGI 2 grade
- Avoid contamination of the grease by dust and/or dirt (More Info) Always avoid contamination of the grease by dust and/or dirt when applying. Preferably use a pneumatic pump system or cartridges.
- Can replace a wide range of greases (More Info) Because of its true Multi Purpose character may replace a wide range of greases, allowing stock rationalization and simplification of maintenance.
- Is a true multi-purpose grease, formulated for lubrication of loaded slide-, ball-, and roller-bearings, wheel bearings, universal joints, chassis, and various shock loaded or vibrating applications in transport, agriculture and off road equipment, operating in wet, dusty and/or dry conditions.
- Suitable as general purpose grease for industrial applications requiring a NLGI 2 grade
- Extreme Pressure grease.
- Forms a durable lubrication film, resulting in reduction of maintenance and down-time costs.
- Miscible with most other conventional soap greases.
- Excellent mechanical stability avoiding ejection or loss of consistency during operation.
- Excellent adhesion to metal.
- Good thermal stability, leading to high resistance to temperature variations.
- Does not contain lead, or other heavy metals considered harmful to human health and the environment.
- Economical – one grease for many applications.
- High EP protects heavily loaded or shock loaded bearings.
- Resists water “wash-out”.
- Excellent for use in centralized lube systems.
- Good anti-rust properties.
- Distinctive, attractive color.
- NLGI #2 Certified LB in chassis applications.
Calcium Grease Definition
Calcium greases were the first, followed shortly after by the lithium and barium greases. Calcium grease became commercially available in the late 1940s. While they offer both water and heat resistance, they can be sensitive to water-becoming firmer or softer under different conditions-and, if overheated, they tend to harden. They do, however, carry high loads in operating bearings without the addition of extreme pressure (EP) additives Complex soap-based greases were developed to improve the heat resistance of previous simple soap based greases. Combinations of additives and oils are carefully selected to maximize the performance of the greases. They generally have good mechanical stability, low-temperature pumpability some will even have good reversibility characteristics and will operate at temperatures which are moderately high. Their dropping point may be 100°F. to 200°F. (38°C. to 93°C.) higher than the dropping point of corresponding soap greases. They are generally formed by reacting a common base with two dissimilar organic acid compounds, such as a normal soap base and complexing agents, generally of short chain metallic or organic materials and made “in situ” (in place) in the grease kettle. This makes greases to meet more demanding requirements. Briefly, typical lithium-based greases (the most common) are made from a fatty acid, usually 12-hydroxystearic acid, and a lithium base to produce a simple soap which acts as the grease thickener. Components are then added to give it EP and other desirable properties that allow equipment to run at peak performance. In the 1930s and 1940s, researchers started to find new thickeners for “multipurpose” greases.
Calcium Grease Applications
- Recommended for lubrication of wire ropes metal cables, chains, slide rail and open gears found in marine off-shore and industrial applications.
- Can be used in all types of anti-friction and plain bearings
- Suitable for miscellaneous components (More Info) such as gears, cams, slides, etc.
- Excels in EP performance
- Automotive applications such as chassis, ball joints,(more) universal joints and wheel bearings
- Industrial applications such as continuous casters, conveyors, ball mills, crushers, off-shore and underwater applications.
- Used in motor-operated steam valves to control high-pressure steam(More Info) These steam valves are typically found in nuclear plants and thermal-generating stations(more) An article in NLGI Spokesman, July 20022, supports that the calcite particles, inherent in calcium sulfonate greases, make them a good choice for high-temperature applications.
- Beneficial for rust performance (More) Calcium sulfonate greases are generally beneficial for rust performance, with oxidation stability considered good or excellent. Rust inhibitors are surfactants that neutralize acids on the surface of metal. They can also make an oily surface, or barrier, to stop rust on the surface. Although the thickener can affect oxidation, it is often based on the oil’s quality.
- In summary, if the application requires H-1 approval, heat resistance or water tolerance, a properly manufactured calcium sulfonate grease that meets your needs may be worth the price.
Calcium Grease CHARACTERISTICS
- Very adhesive.
- High temperature resistance
- Excellent water resistance for general lubrication under very severe conditions ( heavy loads, shocks, vibrations, dust and water ).
- High Dropping point ( The drop point is above 300°c
- Good EP properties
- Excellent properties at high loads due to the high viscosity base oil and Calcium Sulphonate complex
- excellent mechanical stability in roller bearings (all kinds of bearings) slide ways and joints
- excellent oxidation and corrosion protection
- Lubrication intervals are greatly extended as well as reducing maintenance and costs.
- Good shear stability
- Long life in storage and in service.
- Highly resistant to ”bleeding” or separation
- Unparalleled rust and corrosion protection – semi-permanent protection of metal surfaces.
- Will not wash off — excellent resistance to water washout and water spray off.
- Handles low-speed, heavily loaded equipment-natural extreme-pressure properties and heavy base oil.
- For use with no food contact.
Bentonite Grease Definition
Bentonite Grease(Extreme Pressure) is an in-organic clay based grease for plain and rolling bearings operating at temperatures higher than those at which conventional soap based greases can be used. This grease is amber colored multipurpose grease containing anti-corrosion and EP additives and is suitable for most conditions especially at elevated temperatures. The grease performance is limited only by the properties of the base oil. This grease will give excellent service life at temperatures in excess of 160°C, provided the re-lubrication period is suitable adjusted. This grease is mostly used for fans, plumber blades underground mining, plastic injection molders, etc.
Bentonite Grease Applications
- Recommended for use in bearings operating at high temperature where conventional soap thickened greases fail due to the high temperature
- Suitable for use in heavily loaded, medium to large, slow speed bearings commonly found in kilns, steel mills of aluminum, glass and rubber plant
- Recommended temperature range : -20o C – 180oC
- recommended for use in all industrial ball, roller and plain bearings where extremely high temperatures are coupled with heavy loads
- particularly useful in applications where melting-out or dripping of grease would cause damage to production or materials
- Widely used in the equipment of metallurgy, casting and rolling, papermaking machinery and cement production
- Not recommended for automotive use. Do not mix with non-bentone greases.
- High temperature resistant.
- Good sealing properties.
- Resists softening.
- Good EP properties.
- Reduced maintenance.
- No leaking of grease from bearings.
- Non-melting thickener keeps consistency at high temperature
- Good protection against rust and corrosion
- Excellent water-wash out protection and storage stability
- High degree of water resistance.
- Good pumpability characteristics.
- Good sealing properties in dusty conditions.
- Wide temperature range.
Barium Complex Soap Grease Definition
Barium Grease is a technologically advanced range of barium complex soap based greases enhanced with excellent resistance to water washout, aging and acid and alkaline solutions. Shows also excellent performance in combination with hot water and vapour. This makes it a very suitable grease for a vast range of applications. Suitable for use in centralized lubrication systems.
Barium Complex Soap Grease Applications
- Water, acids, alkaline bleach pumps
- Extractors and fans in very wet environments (i.e. cooling waters)
- Plain bearings and bearings in the textile and leather industry
- Mechanisms exposed to vapour in the paper industry
- Wheel bearings in all types of vehicles and moving equipment
- Driers in the wood industry
- Chains and roller belts in the packing industry
- Anticorrosive protection in sprayers walls
- Centralized lubrication systems in granulating machines (Grease Barium Complex M 1-2)
- High speed bearing in wet or chemical ambience
- Bearings exposed to vibrations or oscillations in heavy industries
- Sealing grease in labyrinth packing
- Bearing discs
- Cold and hot water tap grease lubrication
- Rotary joints
- Appearance : reddish-yellow or green.
- Works over a wide temperature range.
- Dropping point approximately 220°C.
- Very good water resistance.
- Good mechanical operating stability.
- Very low coefficient of friction.
- Excellent wear protection.
- Outstanding mechanical stability.
- Resistance to water.
- Resistance to many chemicals.
- Low starting resistance.
- Extended lubrication intervals.
Aluminum Grease Description
Aluminum complex grease is a valuable multi-functional, multi-purpose product while no grease can truly be an “all-purpose” lubricant. Aluminum complex greases began to appear in the mid-1960s, and a number of patents were issued over the next several years covering various modifications. Most of the efforts were in the areas of improved water resistance and thermal and mechanical stability. These greases are easy to pump at low temperatures because of their relatively low soap content and higher oil content. The manufacturing of this type grease requires highly competent Grease Makers and sophisticated equipment.
ALUMINUM COMPLEX GREASE Applications
Automobile Wheel Bearings
Aluminum complex greases with special additives are widely used in wheel bearing lubricants for automotive equipment with disc brakes. Because of the higher temperatures generated, other wheel greases could fail in these bearings. The aluminum complex grease stays in place with a minimum of leakage.
Manufacturing and Assembly Plants
Aluminum complex greases have been used as machinery and parts lubricants, especially where very wet conditions prevail. They are also widely used as Food Grade greases.
Extreme pressure versions of aluminum complex greases have been used to lubricate hot and cold rolling mills, hot roll tables and other high temperature applications. Its reversibility, or ability to retain consistency after repeated heating and cooling, is unique. These greases are easily handled in centralized systems and/or bulk storage. The high water resistance of aluminum complex grease is also very helpful in these applications. The water resistance reduces leakage and the amount of lubricant in discharge water.
Aluminum complex grease has been used successfully to grease trailer wheel bearings and hitches. The excellent water resistance makes this grease a “natural”.
Lithium and anhydrous calcium greases have been tried on the wet and dry ends of the mill with limited success. Aluminum complex grease now lubricates both ends with no problems.
This lubricant is used to lubricate the Bunbury mixers where they can be wet, hot and corrosive atmospheres.
Aluminum complex grease can be used for almost every application requiring lubricating grease. It stays in the bearings and reduces spotting of the cloth. It is also claimed that aluminum complex grease will scour out of the cloth being processed.
Farming and Construction
Aluminum complex grease is used as a general purpose lubricant and a bearing grease. Properly inhibited, it protects equipment from rust.
- Excellent water resistance
- Respond well to additive treatment
- Excel in resistance to washing out of a bearing
- Unique advantages suited to elevated temperatures
- High dropping point
- Excel in resistance to being washed off a flat surface
- Low Lubricant consumption
- High ability to restructure after excursions that are above soap’s melting point.
- Good pump ability
- Economic formulation
- Low soap content
- Combines well with chemical extreme pressure (EP) agents
- Excellent surface adhesion
- Long shelf life
Grease is a semisolid lubricant. It generally consists of a soap emulsified with mineral or vegetable oil. The characteristic feature of greases is that they possess a high initial viscosity, which upon the application of shear, drops to give the effect of an oil-lubricated bearing of approximately the same viscosity as the base oil used in the grease. This change in viscosity is called shear thinning. Grease is sometimes used to describe lubricating materials that are simply soft solids or high viscosity liquids, but these materials do not exhibit the shear-thinning properties characteristic of the classical grease. For example, petroleum jellies such as Vaseline are not generally classified as greases.
Greases are applied to mechanisms that can only be lubricated infrequently and where a lubricating oil would not stay in position. They also act as sealants to prevent ingress of water and incompressible materials. Grease-lubricated bearings have greater frictional characteristics due to their high viscosity.
Powdered Solid Greases
Powdered solids may also be used as thickeners, especially as clays, which are used in some inexpensive, low performance greases. Fatty oil-based greases have also been prepared with other thickeners, such as tar, graphite, or mica, which also increase the durability of the grease.
Engineering Assessment & Analysis
Lithium-based greases are the most commonly used; sodium and lithium-based greases have higher melting point (dropping point) than calcium-based greases but are not resistant to the action of water. Lithium-based grease has a dropping point at 190 to 220 °C (350 to 400 °F). However the maximum usable temperature for lithium-based grease is 120 °C. The amount of grease in a sample can be determined in a laboratory by extraction with a solvent followed by e.g. gravimetric determination.
Gear greases consist of rosin oil, condensed with lime and stirred with mineral oil, with some percentage of water. Special-purpose greases contain glycerol and sorbitan esters. They are used, for example, in low-temperature conditions. Some greases are labeled “EP”, which indicates “extreme pressure”. Under high pressure or shock loading, normal grease can be compressed to the extent that the greased parts come into physical contact, causing friction and wear.
EP grease contains solid lubricants, usually graphite and/or molybdenum disulfide, to provide protection under heavy loadings. The solid lubricants bond to the surface of the metal, and prevent metal-to-metal contact and the resulting friction and wear when the lubricant film gets too thin.
Solid additives such as copper or ceramic powder are added to some greases for static high pressure and/or high temperature applications, or where corrosion could prevent dis-assembly of components later in their service life. These compounds are working as a release agent. Solid additives cannot be used in bearings because of tight tolerances. Solid additives will cause increased wear in bearings.
Grease General Materials
A true grease consists of an oil and/or other fluid lubricant that is mixed with a thickener, typically a soap, to form a solid or semisolid. Greases are a type of shear-thinning or pseudo-plastic fluid, which means that the viscosity of the fluid is reduced under shear. After sufficient force to shear the grease has been applied, the viscosity drops and approaches that of the base lubricant, such as the mineral oil. This sudden drop in shear force means that grease is considered a plastic fluid, and the reduction of shear force with time makes it thixotropic. It is often applied using a grease gun, which applies it to the part being lubricated under pressure, forcing the solid grease into the spaces in the part.
Classification and standards
Jointly developed by ASTM International, the National Lubricating Grease Institute (NLGI) and SAE International, standard ASTM D4950“standard classification and specification for automotive service greases” was first published in 1989 by ASTM International. It categorizes greases suitable for the lubrication of chassis components and wheel bearings of vehicles, based on performance requirements, using codes adopted from the NLGI’s “chassis and wheel bearing service classification system”:
- LA and LB: chassis lubricants (suitability up to mild and severe duty respectively)
- GA, GB and GC: wheel-bearings (suitability up to mild, moderate and severe duty respectively)
A given performance category may include greases of different consistencies. The measure of the consistency of grease is commonly expressed by its NLGI consistency number.
The main elements of standard ATSM D4950 and NLGI’s consistency classification are reproduced and described in standard SAE J310“automotive lubricating greases” published by SAE International.
Standard ISO 6743-9 “lubricants, industrial oils and related products (class L) — classification — part 9: family X (greases)”, first released in 1987 by the International Organization for Standardization, establishes a detailed classification of greases used for the lubrication of equipment, components of machines, vehicles, etc. It assigns a single multi-part code to each grease based on its operational properties (including temperature range, effects of water, load, etc.) and its NLGI consistency number.
The Difference Between Grease & oil
Grease and oil are both common lubricants used in bearings. The main difference between grease
and oil is that grease consists of an oil and a thickener. The thickener acts like a sponge that retains the oil.
Grease can also contain various additives such as rust inhibitors, EP (extreme pressure) additives, oxidation
preventatives, etc. Typically greases will have a semi-solid to solid consistency. This consistency allows
grease to stay in place longer than oil. For many applications, the ability to stay in place and slowly release
oil gives grease an advantage over oil alone.
Oil and grease are two very familiar terms, but most people aren’t clear on exactly what the difference is… unless they happen to work in lubrication, that is! There are some situations where an oil is the better choice, and some when a grease works better. So, what is the difference between an oil and a grease? read below
- Greases are actually oils with thickener added.
- At room temperature, greases are usually solid, while oils are usually liquid.
- All oils can be turned into greases, but not all greases come from oils.
- Greases are typically only used on machinery, tools, or equipment, while oils have a multitude of other, non-industrial uses.
Some greases need to be food safe, or food-grade (the terms mean the same thing). This means that if they accidentally end up in an items that is meant to be consumed by people or animals, they will not cause any harm, as long as they are found below a specific concentration. (Note: just because a grease is labeled ‘Food Safe’ doesn’t mean you can cook with it. You can’t!) Interflon makes several food-safe lubricants. Read more in this post called “What is a food-grade lubricant?”
Grease is an extremely important part of our modern, industrialized world… so much so that it even has its own institute, where people do nothing but think about grease all day long! It’s called the National Lubricating Grease Institute (NLGI).
The NLGI offers a scale for consistency. This rates greases based on their relative firmness, from 000 (fluid, like cooking oil) to 6 (very hard, like cheddar cheese). Again, your choice of grease is going to be determined by the type of application you’re using it for. Very fluid greases can be used in low-speed applications where there is no danger of leakage. Harder greases can be used in high-speed applications.
Choosing Right Grease Tips
When selecting a grease, you must consider the application and operating conditions in which the lubricant will function. For a better understanding of what goes into a good grease, concentrate on its components, including the base oil type, thickener type and base oil viscosity.
1. Base Oil Viscosity
2. Base Oil Type
3. Thickener Type
4. Performance Properties
Types of Thickeners
The thickener defines the type of grease. There are three or four different types of materials that go into thickeners. The focus in this article is on organic thickeners such as lithium stearate, sodium dodecylsulfate and diurea. There are simple greases and complex greases, depending on the types of fatty acids used.
Lithium: Because lithium soaps are very efficient thickeners, lithium 12-hydroxystearate greases are the most prevalent. Lithium greases provide good lubricity and have great shear stability, thermal resistance and relatively low oil separation. Antioxidants are added to improve oxidative resistance (see Figure 2).
Calcium: These greases have better water resistance than lithium greases. They also have good shear stability. However, they have low-dropping points, do not have good operating temperature range and can only be used in operating conditions up to 110 C (230 F).
Sodium: These greases offer high-operating temperature, up to 175 C (347 F) but are confined to operating conditions no higher than 120 C (248 F) because of poor oxidative stability and high oil bleed. They also are not very water resistant. However, they do provide good lubricity and shear stability.
Aluminum: These have excellent oxidative resistance and good water resistance. But they have a low-dropping point of only 110-115 C (230-239 F). Their usage is generally limited to operating conditions less than 80 C (176 F). When these greases overheat in bearings, they cause sharp torque increases.