30 minutes with Mr. Anjeeve George

1. What are the unique lubrication challenges in the steel industry and how can they be addressed?

In steel plants, you can't use all the commonly used lubricants in all the applications, as many of the applications have a high risk of fire accidents. The material being handled includes molten metal, red hot steel, and hot steel, and in addition, most of the processes involve high-temperature operations. Mineral / petroleum-based oils are the most used lubricants in normal industries. Any leak of lubricants in steel mills, especially those in hydraulics, could lead to highly disastrous accidents. If a high-pressure spray of leaked oil from a hydraulic system is exposed to a hot surface like red hot steel, it will cause fire and propagate by itself. Therefore, we need to use fire-resistant hydraulic fluids that are designed to prevent fires from propagating. Fire-resistant fluids may not be fireproof, but rather fire-resistant, meaning they have properties like self-extinguishing, non-propagating flames, and stop continuing to burn once the source of the fire is removed, even if it burns in the presence of fire. The analogy in our common life is PVC pipes, which are used in electrical wiring because they are fire-resistant. Please note, they are not fireproof.

Mineral oil-based fluids are primarily containing hydrocarbons and have a high heat of combustion, which means they can sustain a fire once it is initiated. Fire-resistant fluids are the remedy for this, and the fire resistance mechanisms are not the same for all the fluids. There are two types of fluids: water-containing and water-free synthetic fluids. Water is a natural and the most widely used fire retardant, and the same is used to provide fire resistant properties for water containing fluids. Water glycol (HFC), invert emulsions (HFB), and high-water base fluids (HFA) are the common water containing fluids in hydraulics. Water does not have any lubrication properties required for normal hydraulic components, can cause erosion on components, and the fluid maintenance is high. The metal parts immersed in the fluid are generally protected from rust and corrosion, but those exposed to air may get rust or corrosion. HFC fluids are the most widely used fire-resistant hydraulic fluid.

However, formulation of water-free synthetic fluids follows a different approach. They are made of materials having properties like low heat of combustion, low hydrogen-to-carbon ratio, halogenated molecules, etc. Phosphate ester (HFDR), polyol ester (HFDU), and polyalkylene glycol (HFDU) are the commonly used water-free synthetic hydraulic fluids. Among these fluids, phosphate ester fluids possess the highest fire resistance and lubricity, but their usage is declining due to fluid maintenance issues and environmental and health concerns. Polyalkylene glycols are the newest in industrial applications, and the polyol esters are the most widely used

Particulate contamination is the major challenge in steel mills, especially the ingressed contamination from the environment. If it can be addressed properly, the hydraulic system will be healthier and give excellent component life. Besides contamination, all the alternate fluids need relatively more care and maintenance compared to that of mineral oil based fluids.

2. How do hydraulic systems impact lubrication requirements in steel manufacturing?

In general, hydraulic systems have a significant impact on lubrication requirements due to their high-power density. Hydraulic components are relatively small compared to their electrical or mechanical analogues operating on the same power. Since the components are small, the contact stress will be extremely high. This leads components to boundary lubrication conditions that need a properly formulated, good quality hydraulic fluid. In steel mills, the priority is not the same as in other normal hydraulics, and fire safety is the primary concern. While selecting a hydraulic fluid, fire safety will be the primary focus, which may lead to compromising lubricant properties.

Basically, hydraulic components are designed for applications with mineral oil-based AW hydraulic fluids. All the properties of fire-resistant fluids may not be the same as those of AW mineral oil fluids. They may vary in lubricity, pressure viscosity coefficient, specific gravity, etc. While using fire-resistant hydraulic fluid in a system, make sure that the components are rated with the respective fire-resistant hydraulic fluid, seals and elastomer components are compatible, and the fluids meet the quality recommendations of the component manufacturer. In addition, some system modification may also be required if the system fluid needs to be changed to a fire-resistant hydraulic fluid.

3. Can you share your expertise on selecting the right lubricants for steel industry applications, considering factors like temperature, pressure and contamination?

Hydraulics is the segment where maximum types of lubricating fluids are used, including mineral oil based fluids like conventional AW, zinc-free AW, VI improved, engine oil, ATF, UTTO, STOU, fire resistant water containing like water glycol, invert emulsions, standard emulsion, water-free fire resistant hydraulic fluids like phosphate ester, polyol ester, polyether polyol, environmentally friendly fluids like synthetic esters, try glycerides, polyalphaolefin related hydrocarbon, polyalkylene glycol, and specialty lubricants like MIL- Spec fluids.

Selection of hydraulic fluids depends on multiple factors such as nature of application, operating pressure, temperature, speed (RPM), components used, safety requirements, fluid maintenance, environmental factors, etc.

For instance, equipment in a steel mill that is in the vicinity of any possible fire hazards needs to use a fire-resistant hydraulic fluid (FRHF). It doesn’t mean that all FRHF fluid can be considered. Primarily, we need to decide between water-containing and water-free synthetic fluids. Then the ratings with components used, expected performance level, fluid maintenance, component life expectancy, environmental factors, system design, OHS, etc. are to be considered. In addition, material compatibility, including elastomer compatibility, and filter compatibility also need to be considered.

4. How do you ensure compatibility between lubricants and materials used in steel production, such as metals and seals?

As discussed, different types of fluids are used in hydraulics, and the chemistry of the fluids is not the same. In a hydraulic system, there are components made of different metals, alloys, plastics, and elastomers, different coatings and paints, materials like cellulose, and fiberglass. The compatibility of each material with each type of fluid is different. In addition, the hydrolyzed products generated due to water contamination and fluid degradation products also need to be compatible with the materials used in a system. For instance, water-containing fluids can't be used with cellulose filters, and certain metals like aluminium, zinc, and lead in pure form will react with the acidic materials generated through the hydrolysis of esters.

In steel plants, it is essential to ensure the compatibility between lubricants and materials used in hydraulic systems, as they use multiple types of hydraulic fluids. While changing a fluid with another type of fluid, it is inevitable to know the interaction between the fluid and the materials used in the system. For instance, the most common elastomer used for making hoses and seals is NBR, and it is not compatible with certain fluids, such as phosphate esters, and can break down quickly. Even certain alloys can behave differently towards different fluids due to their unique metallurgy. Therefore, it's essential to ensure that all materials, including rubber components and other system components, are compatible with the selected fluid. Chemical compatibility is a critical factor in fluid selection, as it involves multiple types of materials and potential reactions.

5. What role do you see lubrication playing in reducing energy consumption and improving efficiency in steel manufacturing?

In steel manufacturing, many of the operations are susceptible to fire accidents in case of hydraulic fluid leaks on it; hence, safety takes precedence over any other factor like energy conservation, component life, and fluid longevity. The energy conservation approach has two factors: 1. improved system efficiency, 2. usage of energy efficient fluids. The fire-resistant fluids are not energy efficient, and the entire contribution to energy conservation is dependent on improved system efficiency. As in any other industry, steel mills also upgrade their systems with energy efficient systems and are committed to energy conservation and a reduced carbon footprint without compromising the safety aspects.

Each application has different priorities, and they use different fluids accordingly. For instance, environmentally friendly fluids are prioritized for environmental friendliness, while food-grade fluids ensure consumer safety in food processing. Likewise in steel mills, fire-resistant fluids are recommended, which may not be energy efficient. However, environmentally friendly options like synthetic esters (HEES type) and polyalkylene glycol (PAG) are biodegradable, although energy conservation is not the primary focus.

To optimize energy efficiency, the fluid weight per unit volume needs to be reduced, viscosity optimized to reduce resistance to flow, and viscosity index improved to reduce the impact of temperature on fluid viscosity. Most of the alternate fluids, including fire-resistant fluids, and environmentally friendly fluids, have a higher density compared to mineral oil-based fluids. Many of these fluids have a lower viscosity index. These properties affect the energy consumption of hydraulic systems. By selecting the right fluid and viscosity grade based on operating temperatures, it is possible to minimize energy loss, but the contribution will be small. Ultimately, safety remains the top priority, limiting the use of energy-efficient fluids in steel manufacturing.

6. How can lubrication best practices contribute to extending equipment lifespan and reducing downtime in steel?

To extend equipment lifespan and reduce downtime in steel mills, good lubrication practices are essential. In my experience, I've seen examples of steel mills that prioritize fluid maintenance, resulting in hydraulic pumps running for over 25 years without failure. However, many steel mills neglect to maintain clean systems, specifically the fluid cleanliness. In fact, some components have outlasted their production cycles, and we've had to replace them with new ones due to discontinued production.

To achieve such longevity, three key principles must be followed: keep the fluid clean, dry, and cool. In the case of water-containing fluids, dry means no excess water. By adhering to these principles, equipment can run for years, as hydraulic system components are designed to do. Unfortunately, poor practices lead to reduced equipment life and increased downtime. Contamination and improper lubrication are the primary causes of hydraulic failures, accounting for nearly 80% of all cases. Proper fluid management is crucial, as equipment failure is often a result of poor fluid conditions rather than component defects. By prioritizing fluid cleanliness and maintenance, steel mills can significantly extend equipment lifespan and reduce downtime.

7. What training or education do you recommend for professionals in the steel industry to enhance their understanding for lubrication and its importance?

Unlike most mechanical systems, hydraulic fluid is not just a lubricant, but an essential functional component of a hydraulic system. To enhance their understanding of lubrication and its importance in the steel industry, professionals should receive training on the basics of lubrication, as knowing the fundamentals allows for better handling. This foundation is especially crucial for larger systems like steel mills, where multiple fluids are used, and no single recommendation exists for all types of fluids. Understanding the fluids and maintenance practices is vital, particularly for alternate fluids. A typical example is water glycol fluid. Water loss through evaporation affects the fire resistance properties, and excess water alters the performance properties. Inadequate pH may result in rust and corrosion of components. In nutshell, improper fluid maintenance can damage the system.

Proper training is essential to identify issues, interpret laboratory reports, and comprehend the properties of various fluids. Recognizing the critical role of hydraulic fluid as a system component is also vital, as its performance is crucial, and ignorance can lead to system damage. Ultimately, acquiring knowledge on selecting components, replacing them, maintaining fluids and systems, and understanding operating conditions can enhance the machine's life and ensure effective lubrication management.