BECHEM Complex CM 21 Innovative long-term lubricating grease with outstanding water resistance
Contamination with water can significantly reduce the service life of a roller bearing. That’s why we developed a new concept that departs from the established and customary lubricating greases for this application and offers significantly better interaction with water: BECHEM Complex CM 21 is an EP long-term lubricating grease with outstanding corrosion protection that was developed for use in roller and plain bearings subject to increased contact with water.
The diagram shows the unique performance of the EP long-term lubricating grease BECHEM Complex CM 21 in water. If the Shell Roller Test results in extensive mixing of water and lubricating grease, a standard lithium grease only absorbs a small amount of the water, which then largely separates again. Often it will lose important properties, e.g. it reduces its consistency or leads to corrosion.
By contrast, calcium sulfonate complex greases can absorb water without losing key properties. Conventional calcium sulfonate complex greases immediately absorb a high amount of water along with dirt, which has a negative impact on efficient performance.
The newly developed BECHEM Complex CM 21 initially repels water better than customary standard lithium greases. However, it really shines when higher performance is needed by continuously absorbing more water than other greases used for this application.
- Work roller bearings in hot and cold rolling mills
- Bearings for guide rollers in continuous casting plants
- Main bearings in crushers in the cement industry and in mining
- Central lubrication systems in mining
- Heavy machinery and large equipment in the construction industry and mining
- Excellent corrosion protection even to salt or process water
- Outstanding anti-wear and extreme pressure properties
- Excellent adhesion to steel surfaces
- Excellent water resistance
- Outstanding shear stability
In the steel industry, water-intensive environments often lead to problems with the lubrication of rolling bearings and cause corrosion. The BECHEM Water Absorption Test shows how different greases behave in the presence of water: Some absorb it and release it again, while others continuously absorb water.
We wanted to know how much and how fast water is absorbed by water-absorbing and water-repellent thickener systems in lubricating greases and developed a repeatable test setup.
For this project, we investigated the main grease thickener systems used in heavy-duty water-intensive applications in steelmaking and rolling processes. Typical greases are made with lithium, lithium/calcium, calcium sulfonate complex and polyurea based thickeners and are well suited for slow to medium speed applications, can tolerate extreme loads and high temperatures and have high resistance to water, dirt and vibration.
Test results from the BECHEM Water Absorption Test.
The test provides us with answers to our questions:
- Is there a point in time when the water is released from the thickener system again?
- How much water enters the bearing?
- How much grease leaves the bearing?
- What is the effect of the water in the bearing?
- What damage is caused by the grease leaving the bearing?
The perfect lubricating grease for the steel industry must maintain its lubricating performance even when exposed to water, but also have the ability to absorb water.
Reliable test results from the BECHEM Water Absorption Test help to select the right lubricants for these extreme conditions and thus reduce downtime. The results show that some greases absorb water and release it later, while others continuously absorb water. The test provides insight into how the greases perform under extreme conditions and their suitability for various water-intensive applications.
Free water in a bearing can cause corrosion. It is therefore necessary for the grease to form a protective film on the metal surfaces that is adhesive and water-resistant. However, if the grease absorbs and takes up the free water without negatively affecting the lubrication performance, consistency and corrosion, this can be a perfect solution.
Free water in a bearing is undesirable and often comes with dirt particles and can have a severe acidity level. This means that the ultimate goal is to keep the bearing sealed to prevent water and dirt from entering. If water does penetrate the bearing, it is extremely important that the grease is suitable for water application to protect the bearing from corrosion and provide reliable lubrication.
Our Global Market Manager Steel Tim-Oliver Mattern answers questions about the BECHEM Water Absorption Test and the BECHEM lubricating greases for the steel industry.
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