Why right selection/choice of high-temperature greases is critical for industrial applications

Introduction

Most industries have particular protocols in place when machines run at elevated temperatures. Such high-temperature operations necessitate the use of high-quality greases.

However, there are other factors to consider when choosing a high-temperature grease for hot, grease-lubricated machinery. 

The selection of high temperature bearing grease must take into account:

•  Type of oil and oil viscosity index
•  Thickener type 
•  Cohesion of the composition constituted by the oil and the thickening agent
•  Additive composition and properties
•  Ambient and operating temperature
•  Loading & speed
•  Relubrication intervals

With so many factors to consider selecting greases that must withstand severe temperatures is among the most demanding lubrication management considerations. This comprehensive guide covers every aspect of high-temperature greases for industrial applications. 

What are high-temperature greases?

High-temperature greases are top-performing, versatile lithium complex greases produced using an optimised amalgamation of top-notch mineral oil, specialised thickener engineering technology, and an extensively preferred additive mechanism. They are selected to deliver sustainable performance over a broad temperature range while introducing various operational load conditions, velocities, and climatic circumstances.

The high-temperature grease of 500 degrees celsius conserves the lubrication layer. It offers the apparent viscosity required for the proper functioning of your equipment, particularly if it gets subjected to intense loads that generate heat.

High-temperature greases are very effective for lubricating parts such as:

• Roller bearings in use in harsh environments
• Bearings for rolling mills
• Crushing and screening machinery
• Roller bearings for glueing, paper processing, and drying machines 
• Oven racks and hearth rollers for furnaces
• Bearings for oven fans
• Hot-mix asphalt plants
• Conveyors, industrial painting lines
• Equipment for space applications (preferred choice is high-temperature grease 300 degrees)
• Water pumps and electric motors
• Vertical shaft applications

Top five critical benefits of high-temperature grease for industrial use

Here are five benefits of high-temperature grease:

1. Exceptional mechanical and thermal endurance ensures product reliability and quality control across a broader operating temperature range, allowing prolonged relubrication cycles and lower maintenance.

2. Excellent extreme pressure and anti-wear characteristics offer extended component life.

3. Superior water resistance provides additional protection in applications where leakage and degradation are more likely.

4. Excellent corrosion resistance

5. Excellent multifunctional capabilities, which allows for a reduction in product inventory.

How to select high-temperature greases?

A selection methodology needs to be considered carefully before picking a high-temperature grease, either for a single or multiple industrial applications.

The long-term performance of the grease is governed by degradation factors, including- mechanical (shear and stress), oxidative, and thermal stability. Analysing the implications of the exposure to temperatures and the reasons for product degradation is a good place to start while selecting a high-temperature grease.

Thus, evaluating the following high-temperature grease specifications and constituents is critical.

Base oils

The most common base oil component is mineral oils. Understanding the base oil's performance characteristics and its degradation parameters is critical.

Only then can the grease manufacturer choose materials based on their acquaintance with, and maybe the availability of, the resources.

Thickeners

The grease thickeners chosen may be organic, inorganic, or a soap/complex soap, such as lithium or calcium sulfonate complex. Lithium complex-thickened grease provides greater thermal deterioration limits and has higher maximum temperature boundaries than other thickening agents and materials. 

Thus, they are employed in manufacturing high-temperature grease of 1000 degrees.

Additives

Grease additives offer features that resemble lubricating oils, such as oxidation stability, resistance to corrosion, fatigue strength, low-temperature flow characteristics, moisture resistance, etc. 

The additive must be able to interface symbiotically with the thickener and the oil to produce a homogeneous, stable blend of the three constituents.

Ensure compatibility among the high-temperature grease constituents

Grease thinning indicates a lack of compatibility. If thinning occurs at different temperature ranges and time limits, thickeners, additives, and base oils may all have complications. 

Thus, before converting critical systems to a new grease, extensive testing is required to avoid substantial cost and time delays due to prolonged maintenance issues.

Five steps to follow while selecting a high-temperature grease

1. Evaluate the accurate temperature range. The operating temperature could be lower than the optimal range. To determine the working temperature of the grease, utilise a contact or non-contact sensor.

2. Determine whether the requirement for grease is infrequent or continuous. If it is constant, seek a high-quality product that fits the operating demands.

3. Verify that the cooling and heating cycles coincide with the operating and non-operating cycles of the machinery.

4. If relubrication is expected to be problematic, select a high-performance product, even if it is more costly, to obtain a reduced utilisation cost.

5. Take into account any aesthetic concerns. Check to see if the product has dripped onto a component in the process. The operator should calibrate the volume and relubrication frequency against the risk of product degradation.

Conclusion

Choosing the best-in-class high-temperature grease is crucial since the grease quality can impact the equipment's performance. Understanding the selection criteria for different high-temperature greases and their applications is vital. 

Castrol High Temperature Grease - Tribol & MolubAlloy series is unquestionably the finest option. It is engineered to meet environmental concerns, resist rust and oxidation, and provides long-term performance with intermittent exposure to temperatures as high as 343°C/650°F.