Introduction
Grease is a combination of a thickening agent and a liquid lubricant. It is semi-fluid in nature. The primary characteristic of grease is its thickening agent. The percentage of thickeners in a grease is 3-30%. Additives made of grease also include solid components such as graphite, chalk, silica, mica, Teflon and many more. It can also consist of corrosion inhibitors, defoamers and friction-modifiers. The percentage of obtaining grease additives from the grease component is 0-15% where it is 70-90% while obtaining base oils.
Categories of Grease
The grease can be distinguished into two categories:
- Soap Thickened Greases: This type of grease consists of thickening agents such as lithium complex, aluminium complex, calcium complex, calcium sulfonate, barium, etc.
- Non-Soap Thickened Grease: This type of grease consists of organo clay, silica and polyuria.
Working of a Grease
The best way to lubricate the moving parts is an oil bath but this process is not convenient for the machinery. However, grease suspends the oil through the thickening agent and coats the empty space with a grease compound. This process can be called the “time release” process. In this process, the oil present in the grease compound is released when the parts of the machinery start to heat up. This released oil provides lubrication to the parts along with the additives whereas the thickening agent holds on to the oil. The grease is considered to be used when the thickening agent completely releases the lubricant. Thus, grease needs to be added regularly during this process.
How to Determine the correct Grease
It is important for you to know the importance of specific grease you choose as it can help in identifying misapplication. Some of the important aspects to consider while choosing the grease are temperature, characteristics and thickness. Below mentioned are some of the common greases used:
- Lithium and Lithium Complex Grease: This is the most chosen grease among all. It is corrosion resistant, stable for long-term and can have a good wash. It also gives amazing performance during the low temperatures. They can be used in various applications.
- Calcium and Calcium Complex Grease: One of the best characteristics of this greaseis that it is both water and wash resistant. It is capable of carrying high loads and delivers excellent performance during low temperatures.
- Aluminium and Aluminium Complex Grease: This grease is highly recommendable for applications that require high temperatures and frequent washing. This grease is also capable of handling water. It can be used as an extension due to its stringy stiffen nature.
- Polyurea: This grease is often found in ball bearings or electric applications. Some of the characteristics of this grease are low compatibility, low corrosion resistance and excellent performance at high temperatures.
- Bentonite: Bentonite is a clay form of grease. In this grease, the oil evaporates before melting of the clay. It is used in applications where the grease is not required to melt. However, it is not compatible with other types of greases.
Choosing the Correct Grease for the Application
It is important to know that all greases are multi-purpose and are used to meet the requirements of multiple appliances. Thus, some of the important factors that one should consider while choosing the grease are:
- Grease with higher NLGI grease is essential for high operating temperatures.
- Appliances with extremely high temperatures need grease of high dropping point and base oils of high viscosity.
- Appliances with low temperatures need a softer NLGI grease or base oils with low viscosity.
- Appliances having high loads need grease that has the characteristic of handling extreme pressures.
- Most of the bearings take a long time while processing and loading. Thus, it needs grease that can be flexible.
In this situation of grease misapplication, the first step is to determine which type of grease is used. It is important to clean the appliance properly before applying the grease to avoid compatibility issues. Thus, it is essential for you to know your application and the grease for the desired performance.
Aspects to be Considered while Choosing the Correct Grease
Some of the important aspects to be considered while choosing the correct grease for your application are:
- Operating Temperatures: The grease should be chosen according to the operating temperature of the appliances. Excessive temperature can lead to softening of the grease. This can result in oxidation or carbonization.
- Speed: Speed is an important factor while choosing the grease. This is because grease generates a film on the surface that carries out the process of lubrication. Thus, high speed bearings require low viscosity. If the viscosity is high, it will generate excessive heat and increase the consumption of electricity.
- Load: Bearings that operate under high load, require a grease that can generate a protective film layer to sustain the load and minimize the wear.
- Exposure to Corrosive Environment: One of the major functions of grease is to prevent corrosion. However, if the grease is not chosen correctly, it can lead to contamination and reduce its lubrication capacity.
- Intervals of Maintenance: It is important to apply and maintain the grease on regular intervals to control the wear of bearing surfaces.
- Cleanliness Requirements: It is mandatory for you to choose the grease that fulfils the regulations set by Food and Drug Administration and other regulatory bodies, while using it in applications related to the food or pharmaceutical industry.
Take Away
This is the brief explanation about how to choose the correct type of grease for your application along with the factors that need to be considered while choosing the grease. We hope those tips will be effective for you. Please let us know through your valuable feedback and the suggestion in the drop box.