If you’ve asked yourself the question “What is EP grease best used for?”, this detailed blog post will shed light on this subject.
The acronym “EP” simply means extreme pressure.
Characteristics of an EP Grease
The goal of any lubricant is to keep two metal surfaces from coming in contact with each other. When those two metals surfaces are put under extreme shock loading or high pressure, a regular non-EP grease will be pushed past its limit whereby the protective film can no longer withstand the shock load or high pressure, and thus breaks. When this happens, those two metal parts literally come into physical contact with each other, causing unwanted wear and friction.
To overcome such a situation, a lubricant manufacturer will take their normal grease and engineer in extreme pressure additives that may come in the form of liquid or solid lubricants. Solid lubricants such as molybdenum disulfide and graphite are consider extreme pressure additives. Some extreme pressure liquid additives include liquid moly, antimony, etc.
These additives were designed to withstand very high pressures and shock loads. When the basic film of grease and oil would rupture under such tremendous shock loads, these solid and/or liquid EP additives come into play and act as an extra barrier of protection to keep two metal surfaces from coming into physical contact with each other.
These extreme pressure agents literally bond themselves to the surface of the metal, thus preventing metal-to-metal contact. Not only do they withstand heavy shock loads, but they also can reduce friction and wear, greatly extending the life of the parts they are protecting.
Also, when considering EP greases one needs to look at the grease’s consistency and the actual base oil type, viscosity of the base lubricating oil and thickener utilized in the formulation. If the machinery in question operates in difficult and extreme environments where parts will be exposed to heavy shock loads, consider the option of using an EP grease that is formulated with a heavier base fluid, an over-based calcium/sulfonate complex based thickener, and a unique synthetic polymeric technology such as AMSOIL Synthetic Polymeric Off-Road Grease with 5% moly.
To keep a grease from pounding or squeezing out when exposed to extreme pressure and shock loads, it can be helpful that such a grease utilizes adhesive and cohesive additives. These additives give a grease a tacky, or sticky, characteristic.
A tacky grease typically is very difficult to squeeze or pound out. Some added benefits to a grease with adhesive and cohesive properties is its ability to create a very resistant barrier to contamination. Additionally, such a grease will offer superior water washout resistance.
Specifically, What is EP Grease Best Used For?
An extremely high performance, high quality EP synthetic grease is typically formulated to be used in applications where industrial machinery will be operating in very extreme conditions, such as high shock loading, high heat, and moisture.
An EP grease is a perfect choice for chassis points, universal joints, pins, bearings, bushings, slide and cam mechanisms, etc. Any piece or equipment or part that is continually subjected to heavy shocks and loads will be perfect for an EP grease.
If the grease utilizes the solid lubricant molybdenum disulfide, it will offer outstanding protection against scoring of surfaces that either slide, turn, or are oscillating when exposed to extreme loads and heavy shocks. An EP grease is intended for protecting heavily loaded components during the most extreme operating conditions.
It is important to know that molybdenum disulfide, when it has fully plated itself to metal surfaces, can absorb an astounding 500,000 pounds per square inch.
Treating a grease with 5% molybdenum disulfide will provide extra protection against friction, scuffing, and wear. By reducing friction, one is lowering temperatures in bearings, resulting in longer equipment life and less grease consumption.
An EP grease can and should be designed for extreme pressure but all function well in a broad operating temperature range. It should provide extended service even if a part is exposed to high temperature. The vast majority of most greases have dropping points between 280 and 380 degrees. For example, a high performance grease such as AMSOIL Synthetic Polymeric Off-Road Grease NLGI #2 with 5% moly has a dropping point of 650 degrees F. Here is another factor to consider when looking to provide maximum high temperature and extreme pressure protection for your hard working equipment.
Water Resistance Is A Must for an EP Grease
When asking the question” What is EP grease best used for?”, you must keep in mind that for a grease to be truly considered an EP grease, it must be water resistant. If an EP grease is not engineered to offer superior water resistance, then when the grease is exposed to water and moisture, its extreme pressure capabilities will be vastly reduced. Here is an example of how it is important to have a complete understanding and vision of the type of conditions a piece of equipment will be exposed to. It becomes an effort in futility if one purchases and invests in a grease with extreme pressure capabilities but offers poor water resistance.
You may wonder why water resistance is an important feature for an EP grease. There is a water resistance test called the ASTM D-1264 Water Washout Test. Your conventional extreme pressure greases on the market that have been put through this test typically score 10% water washout. The lower the number, the more resistant the grease is to washing away when exposed to water.
Many grease thickeners that are used to create a grease are made up of soap-based thickeners. Imagine if an extreme amount of water is exposed to soap. In simplistic terms, water will literally wash away the soap. Of course, in the case of the manufacturing of greases, we can say that soap is added to the oil to create a grease. The soap thickens the oil to give it its consistency.
Added to these two components, the oil and the thickener, are various additives. These additives can impart water resistance to the grease. Like all lubricants, you get what you pay for. If the goal is to utilize a grease that is extremely water resistant and waterproof, then such a grease requires specialized thickeners and additives to build such a lubricant.
If a grease is used that is not considered a water resistant grease, but is an extreme pressure grease, and the thickener type is soap-based such as a simple lithium-soap grease, then what do you think will happen if an unusual amount of water is suddenly exposed to that grease? If an inordinate amount of water stays in contact with a conventional lithium grease, eventually much of the grease and its additives will literally be washed away.
If this happens, then unfortunately when metal parts are exposed to extreme shock loads and extreme pressure, the grease that was washed away by the water is no longer present to protect the two metal surfaces from coming in contact with each other. A better choice for a water resistant grease would be a thickner type such as an over-based calcium sulfonate complex thickener .
Important Specifications to Look for in an EP Grease
For the sake of this blog post, lets take a look at a specific EP grease that is available today on the market that offers amazing water resistance and extreme pressure capabilities, AMSOIL Synthetic Polymeric Off-Road Grease, NLGI #2, 5% moly .
To determine a grease’s extreme pressure capabilities, there is an industry standard test designated ASTM D-2509 commonly known at the Timken OK Load Test. The higher the number scored, the better a grease’s ability to withstand extreme pressure. Typical EP greases on the market average 35 to 50 pound Timken OK Load results when put through this extreme pressure test.
AMSOIL Synthetic Polymeric Off-Road Grease, NLGI #2, 5% moly was run through this test and scored a 75+ Timken OK Load, a standout result. This same grease, when put through the ASTM D-1264 Water Washout Test, scored a superior 1% water washout.
It is also important to choose the correct NLGI grade grease. NLGI is the acronym for the National Lubricating Grease Institute. The most common and general purpose EP grease will be the NLGI 2 grade.
Compare those two scores to the industry standard of greases found in the market place. It is safe to say that there are specialized extreme pressure greases that could offer far superior protection for those pieces of equipment that are exposed to very extreme pressures and potentially high amounts of water exposure. The two go hand in hand.
The Best EP Grease on the Market
AMSOIL Synthetic Polymeric Off-Road Grease was custom engineered with a proprietary synthetic polymeric formulation to deliver real benefits specifically for off-road heavy equipment. Its one of a kind synthetic polymeric technology gives AMSOIL Off-Road Grease an edge over the competition. It has an outstanding ability to tenaciously cling to metal and stay in place and not be pushed out or squeezed out. It delivers the maximum in extreme pressure and shock load resistance in long term service even when exposed to water and wet environments.
Extreme Pressure and Shock Load Resistance
When heavy equipment components are lubricated with grease, they are typically exposed and subjected to extreme abuse. Almost all heavy duty off road vehicles are exposed and operate under extreme heavy load environments. The grease’s main function when heavy equipment pivot points are greased is to prevent metal to metal contact when subjected to extreme pressure and shock loads. Conventional or inferior quality greases are not able to withstand the extreme pressures and shock loads and are usually squeezed out or pounded out of the impact area.
When conventional greases are squeezed out or pounded out of heavily loaded parts, these parts are left unlubricated, which can lead to metal to metal contact and unfortunately tremendous amounts of unwanted wear and possibly catastrophic failure. Chemists and formulators at AMSOIL created the absolute finest EP grease on the market. Their Synthetic Polymeric Off-Road Grease with 5% moly utilizes an advanced and proprietary synthetic polymeric technology that delivers amazing adhesion, which is an ability to stick to and cling to components.
Also, this exclusive formula offers amazing cohesion, which is an ability to cling to itself. This synthetic grease was custom blended and designed to resist pounding out and absorbing extreme pressures. It outperforms other greases in these highly loaded extreme pressure environments. This grease lasts and will not be pounded out or squeezed out, giving the owner/operator the highest level of lubrication over long service life. Downtime and repair costs are reduced.
5% Moly Fortified
AMSOIL Synthetic Polymeric Off-Road Grease meets Caterpillar’s requirement for pin and bushing applications due to this grease containing the specified 5% moly. It has a 75+ Timken OK Load and has superior Four Ball Weld Point (620+) and Four Ball Wear Test Scar millimetre (<.45) test results that prove its superior load bearing capabilities.
Extended Service Life, Excellent Value
AMSOIL Synthetic Polymeric Off-Road Grease deliver high performance protection over long service life intervals. It is highly resistant to shock loads, extreme pressure, and pounding out. Its unique and proprietary technology will significantly reduce the amount of grease that is squeezed out during repetitive pounding action. AMSOIL Synthetic Polymeric Off-Road Grease’s ability to reduce grease consumption and extend service life is operator determined and application dependent.
With that said, in-field testing results have shown that it is capable of reducing grease consumption by up to 50%. This superior capability can allow heavy equipment operators to either experience less grease consumption per application while maintaining their current maintenance schedule, or it is possible to extend the length of time between maintenance re-greasing intervals.
When you consider that this grease delivers amazing pound out resistance, coupled together with outstanding protection and longer service intervals, the result is a reduction in grease consumption, equipment replacement costs, and labor costs.
So, what is EP grease best used for? If one considers investing in this type of grease, it can effectively be used for realizing much lower grease consumption, a vast reduction in breakdowns, lower repair costs, and prolonged equipment life.