Greases play a crucial role in the world of lubrication, providing essential functions in various industrial applications. This article aims to provide a comprehensive overview of greases, defining their purpose, exploring their primary functions, highlighting advantages over oils, discussing limitations, examining applications, and emphasizing the importance of consulting with lubrication experts.
Grease Anatomy
Grease is a semisolid lubricant composed of a liquid lubricant mixed with a thickener. Because of its complex rheology, grease is a special lubricant with a multiphase formulation containing fluids and solids. Its rheological properties vary with shear rate and duration, behaving like a solid under small loads at normal temperatures and transitioning to a liquid-like state of higher loads.
Grease contains three properties:
Base Oil: Constitutes 80%-95% of grease composition. Mineral oil is the predominant choice for its optimal performance in standard industrial applications. Synthetic base oils are preferred in extreme temperatures, either high or low.
Thickener: Makes up 5%-20% of grease and gives it a semi-fluid to solid consistency. Metallic soaps such as lithium, clay, sodium, aluminum, polyurea, and calcium are commonly used. Complex greases combine metallic and lithium soaps with low-molecular-weight organic acids, known for their high dropping points and efficient load-carrying capabilities. Non-soap thickeners like bentonite and silica aerogel are gaining popularity for their ability to withstand high temperatures and applicability in the food manufacturing process. However, compatibility issues with base oils can lead to faster oxidation and cause more frequent regression.
Additives: Constitute 0%-10% of grease and play a crucial role in enhancing desirable properties, mitigating undesirable ones, and introducing new functionalities. Examples include molybdenum disulfide and graphite, which reduce friction and wear without causing rust on metal surfaces, particularly under slow speeds and heavy loads.
Primary Functions of Greases
Reduce Friction: Lubrication reduces friction by forming a thin film between moving surfaces, minimizing direct contact and preventing metal-on-metal rubbing. This reduces frictional forces, resulting in smoother operation and less heat generation.
Minimize Wear: Grease forms a protective film between moving surfaces, reducing wear and friction, extending the lifespan of parts, and maintaining equipment in good condition.
Seal Against Contaminants: Grease is a sealant that minimizes leakage and keeps out contaminants, offering a sealed system for machines and equipment. Its consistency prevents lubricant leakage, blocks corrosive contaminants, and maintains the effectiveness of deteriorated seals.
Prevent Rust and Corrosion: Machineries in varying climates are susceptible to corrosion, compromising component integrity and speeding up breakdown. Lubricating grease provides high corrosion protection by insulating machinery with a layer that prevents water ingress and subsequent corrosion.
Advantages of Grease over Oil
Oil and grease prevent metal-on-metal contact and protect equipment from wear, but the two are not interchangeable. Here are some advantages of using grease over oil:
Adherence to Surfaces: Greases adhere well, especially in vertical or overhead applications, ensuring continuous lubrication.
Longer Lubrication Intervals: The grease’s semisolid nature allows less frequent maintenance than oils. Grease is effective in equipment for longer periods and withstands diverse conditions.
Effective in Sealed Systems: Grease excels in leakage control and provides superior seals against contaminants. Ideal for applications where reliable, stationary lubrication is required.
Limitations of Grease
Temperature Sensitivity: Grease cannot dissipate heat through convection like circulating oil because of its consistency. At higher temperatures, grease separates more quickly, causing the thickening agent to separate from the base oil that acts as a lubricant.
Resistance to Flow: Grease’s semisolid nature limits its flow ability compared to oils, impacting specific lubrication scenarios. It has a higher resistance to motion at start-up than oil, making it unsuitable for low torque/high-speed operations. Because of their viscosity, greases are unsuitable for high-speed applications, unlike liquids.
Storage Stability: Extended storage can separate the base oil and thickener, altering the grease’s properties.
Limited Reach: Greases may not effectively reach all areas requiring lubrication, especially in complex or hard-to-access machinery.
Applications of Greases
Automotive Industry: Grease is crucial in automotive applications, including wheel bearings, chassis components, and mechanical linkages. It withstands heavy loads, protects against corrosion, and ensures smooth operation.
Industrial Machinery: In manufacturing plants, power generation, and milling operations, industrial grease lubricates bearings, gears, conveyors, and chains. It provides reliable lubrication in high-load, high-speed applications, reducing friction and preventing wear.
Construction and Heavy Equipment: Grease is essential for construction machinery like excavators, bulldozers, cranes, and mining equipment. It protects against dust, water, and heavy loads, ensuring smooth operation and minimizing downtime.
Marine Applications: Marine equipment such as ship propulsion systems, winches, and steering mechanisms rely on grease lubrication. Its water resistance and adhesion properties prevent corrosion and maintain reliable performance in the harsh marine environment.
Food and Beverage Industry: Food-grade greases meet stringent safety standards for processing machinery, packaging equipment, and conveyor systems. They provide lubrication while ensuring compliance with hygiene regulations, making them safe for incidental food contact.
Consult with Lubrication Consultants
Get the correct grease lubricant solutions for your business with Fluid Solutions. Since 2008, we’ve been delivering superior lubrication solutions to manufacturing industries, steel production, sugar mills, coconut oil mills, and the food and beverage sectors in the Philippines.
Fluid Solutions delivers unmatched quality and expertise, whether you need high-temperature greases, gear coupling greases, or multi-purpose greases for all industrial applications.
Call Fluid Solutions at (02) 8370 5928 / (0917) 894 9156 or send us an email at inquiry@fluidsolutions.com.ph for your inquiries or if you want to get tailored guidance for your business. You can also reach us via our official website or social media pages for any lubrication concerns.
