Lubricants and Industrial Oils: How to Choose the Right Type Based on Operating Conditions and Materials

Photo: Isis França / Unsplash

Choosing the right lubricant or industrial oil can significantly impact the lifespan of machine components, energy efficiency, and operating costs. While mineral oils offer proven performance at an affordable price, synthetic variants excel in extreme temperatures, and biodegradable products reduce environmental impact. The key is to consider not only viscosity and additives but also compatibility with seals, metals, or plastics that come into contact with the lubricant. This article compares the properties of different types and will help you avoid common mistakes when making your selection.

Basic Classification of Lubricants and Industrial Oils by Composition

Lubricants and industrial oils are divided into several basic categories based on their chemical composition and physical properties. The most widespread group consists of mineral oils, produced by refining crude oil. They are characterized by good stability, a wide temperature range, and a favorable price, making them suitable for most standard applications. Synthetic oils, produced through chemical synthesis, offer higher performance under extreme conditions—they withstand high temperatures, oxidative stress, and have low volatility. Synthetic bases include, for example, polyalphaolefins (PAO), esters, or polyalkylene glycols (PAG). Semi-synthetic oils combine the advantages of both types and represent a compromise between cost and performance.

Another important group consists of lubricants based on vegetable oils, which are used where biodegradability and low toxicity are emphasized. These products are often certified according to ecological standards and are suitable for applications in the food industry, agriculture, or sensitive ecosystems. For special purposes, lubricants with solid additives such as graphite, molybdenum disulfide, or PTFE are also used, which improve sliding properties under high pressures or in environments with insufficient lubrication.

How to Choose a Lubricant Based on Operating Temperatures and Pressure

Temperature and pressure are among the key factors influencing the selection of the right lubricant. At low temperatures (below 0 °C), the viscosity of the oil is crucial—excessively high viscosity can lead to insufficient lubrication and increased wear. Conversely, at high temperatures (above 100 °C), there is a risk of oil degradation, loss of lubricity, and deposit formation. For extremely high temperatures (up to 300 °C), synthetic oils with high oxidative stability or lubricants with solid additives are used, as they retain their sliding properties even under thermal stress.

Pressure conditions also require a specific approach. Under high loads (such as in gear transmissions or bearings), it is necessary to use a lubricant with high film strength, often enriched with anti-wear (AW) or extreme pressure (EP) additives. These additives form a protective layer on metal surfaces and prevent direct contact. For applications with variable loads, oils with a high viscosity index are suitable, as they maintain a stable lubricating film even under fluctuating temperatures and pressures.

Photo: Fulvio Ciccolo / Unsplash

Lubricant compatibility with materials and environment

When selecting a lubricant, it is essential to consider compatibility with the materials that come into contact with the lubricant. Some oils may react with rubber, plastics, or non-ferrous metals (such as copper), leading to their degradation or loss of functionality. Synthetic ester-based oils, for example, are known for their aggressiveness toward certain types of elastomers, whereas mineral oils are generally more gentle. Therefore, it is advisable to perform a compatibility test before using a new lubricant, especially in critical applications.

The environment in which the lubricant operates also plays a key role. In the food industry or pharmaceuticals, lubricants approved for food contact (e.g., with NSF H1 certification) are required, meeting strict hygiene standards. In environments with high humidity or dust, it is necessary to choose a lubricant with good resistance to water and contaminants, often with additives against corrosion and emulsion formation. For outdoor applications or operation in aggressive chemical environments, special oils with high chemical stability and protective additives are used.

Maintenance and Monitoring of Lubricant Condition to Extend Equipment Lifespan

Regular maintenance and monitoring of lubricant condition are crucial for ensuring the long lifespan of machinery and minimizing repair costs. The basic step is adhering to recommended oil change intervals, which depend on the type of lubricant, operating conditions, and machine load. In industrial operations, centralized lubrication systems are often used, ensuring even and precise lubricant dosing, thereby reducing the risk of over-lubrication or insufficient lubrication.

To monitor lubricant condition, analytical methods such as viscosity measurement, water content, acidity (TAN), or the presence of metal particles are used. These parameters provide information on oil degradation and wear of machine components. Modern sensors and online monitoring systems enable continuous lubricant condition tracking and early detection of issues such as contamination or oxidative degradation. Proper lubricant maintenance not only extends equipment lifespan but also increases its reliability and operational efficiency.

Photo: Robert Laursoo / Unsplash

Impact of Viscosity and Additives on Lubricant Performance in Various Applications

Viscosity is a key parameter that determines the lubricant's ability to form a stable film between friction surfaces. Too low viscosity leads to insufficient surface separation and increased wear, while too high viscosity increases friction and energy losses. For high-speed applications, such as electric motors or turbines, low-viscosity oils (e.g., ISO VG 32 or 46) are typically chosen, ensuring rapid heat dissipation and minimizing resistance. Conversely, for slow-moving mechanisms with high loads, such as gearboxes or bearings in heavy machinery, highly viscous oils (ISO VG 220 and higher) are more suitable, as they better withstand extreme pressures.

Additives play a crucial role in adapting lubricants to specific operating conditions. Anti-wear additives (e.g., zinc or phosphorus compounds) protect surfaces under boundary lubrication, while antioxidants extend oil life by slowing its oxidation. In environments with high humidity or corrosion risk, anti-corrosion additives are essential, forming a protective layer on metal surfaces. For extreme pressures (EP – Extreme Pressure), sulfur- or chlorine-based additives are used, which chemically react with the surface to prevent damage. The selection of the right additive combination depends on the specific application and must be verified by standard test methods.

Specifics of Lubrication in the Food and Pharmaceutical Industries

Lubricants for the food and pharmaceutical industries must meet strict hygiene and safety requirements. According to REACH regulations and food contact standards (e.g., NSF H1), these products must be non-toxic, odorless, and resistant to steam sterilization or chemical agents. Synthetic oils based on polyalphaolefins (PAO) or polyalkylene glycols (PAG) are typically used, as they have low volatility and high stability. For applications involving direct food contact, only H1-registered lubricants are permitted, while for indirect contact (e.g., bearings outside the production line), category H2 is sufficient.

In addition to chemical safety, resistance to frequent cleaning and disinfection is also important. Lubricants in these operations must withstand high temperatures (up to 200 °C during sterilization) and aggressive cleaning agents without losing their properties. For extreme conditions, special greases with a high dropping point (above 250 °C) and water-resistant additives are recommended. Regular monitoring of the lubricant's condition is essential, as contamination by microorganisms or residues of cleaning agents can lead to lubricant degradation and compromise product quality.

Ecological Aspects and Biodegradable Lubricants: When and Why to Choose Them

Biodegradable lubricants are becoming an increasingly important choice for applications in sensitive ecosystems, such as forestry machinery, agricultural equipment, or hydraulic structures. These products are made from renewable raw materials, such as vegetable oils (rapeseed, sunflower) or synthetic esters, and decompose in nature within a few weeks to months. According to the CLP Regulation, they must be labeled as readily biodegradable, which is confirmed by standard toxicity and ecotoxicity tests. Their main advantage is minimizing the risk of soil and water contamination in the event of leaks or accidental spills.

Despite their ecological benefits, biodegradable lubricants have some limitations. Their thermal and oxidative stability is usually lower than that of mineral or synthetic oils, which restricts their use at high temperatures (above 100 °C) or in long-term applications. Their price is also often higher, which can be a limiting factor for widespread adoption. Operators should consider the cost-benefit ratio—however, in areas with strict environmental regulations (e.g., protected landscapes) or when working near water sources, these products are a necessity.

Need help with your selection?

Each lubricant requires individual assessment based on the specific application. GCG Group provides detailed technical data sheets and safety data sheets (SDS) for all products, and our experts will be happy to advise you on selecting the optimal solution for your operating conditions. Contact us – or browse our catalogue of over 1,300 products.