Water contamination is one of the most common challenges affecting bearing lubrication performance. In industries such as steel manufacturing, paper production, marine equipment, food processing, and outdoor machinery, bearings are frequently exposed to water spray, humidity, cleaning processes, and direct water contact.

When water enters a bearing lubrication system, it can reduce grease adhesion, wash away lubricant, accelerate corrosion, and significantly shorten bearing service life.

Understanding water washout effects on bearing grease and selecting the correct water resistant grease are essential for reliable equipment operation.

What Is Grease Water Washout?

Grease water washout refers to the removal or displacement of grease from a bearing or lubrication area due to water exposure.

Water can enter equipment through:

• Direct water spray
• High-pressure cleaning
• Rain exposure
• Condensation
• Humid operating environments

When grease cannot maintain adhesion, the lubricant film becomes insufficient and bearing protection decreases.

1. Loss of Lubricating Film

The primary effect of water washout is the reduction of grease coverage on bearing surfaces.

Consequences include:

• Increased friction
• Metal-to-metal contact
• Higher operating temperature
• Accelerated wear

In severe cases, insufficient lubrication can lead to premature bearing failure.

2. Bearing Corrosion

Water promotes corrosion, especially when combined with:

• Oxygen
• Metal particles
• Industrial chemicals

Corrosion can damage:

• Bearing raceways
• Rolling elements
• Lubrication surfaces

Rust particles may further accelerate abrasive wear.

3. Grease Structure Damage

Water may affect grease consistency by changing the relationship between:

• Base oil
• Thickener
• Additives

Possible results:

• Grease softening
• Oil separation
• Reduced adhesion
• Lubrication failure

4. Reduced Grease Service Life

Water contamination accelerates:

• Oxidation
• Additive depletion
• Grease degradation

Equipment may require more frequent relubrication, increasing maintenance costs.

Common Applications Affected by Water Washout

Steel Industry

Examples:

• Rolling mills
• Continuous casting equipment
• Cooling systems

Challenges:

• High-pressure water spray
• High temperature
• Heavy loads

Recommended:

• SKF LGWM 2
• SKF LGEP 2

Paper Industry

Challenges:

• Continuous moisture exposure
• High operating hours
• Corrosive environments

Recommended:

• Klüber STABURAGS NBU 12

Marine and Outdoor Equipment

Challenges:

• Salt water
• Humidity
• Rain exposure

Recommended:

• Molykote G-4700

Food Processing Equipment

Challenges:

• Frequent cleaning
• Water spray
• Hygiene requirements

Recommended:

• NSF H1 food-grade grease:
• Klüber Klüberfood NH1 94-301

How to Select Grease for Wet Environments

A suitable water resistant grease should have:

1. Excellent Water Resistance

The grease should maintain consistency and adhesion when exposed to water.

2. Strong Adhesion

Good adhesive properties help prevent grease from being washed away.

3. Corrosion Protection

The grease should protect metal surfaces against rust and corrosion.

4. Mechanical Stability

The grease should maintain its structure under:

• Vibration
• Heavy loads
• Continuous operation

Solutions to Reduce Water Washout Problems

1. Select Proper Water-Resistant Grease

Avoid using standard general-purpose grease in wet environments.

Choose grease based on:

• Water exposure level
• Temperature
• Load
• Speed

2. Improve Sealing Protection

Effective sealing reduces:

• Water ingress
• Contamination
• Grease loss

Inspect seals regularly for damage.

3. Avoid High-Pressure Water Directly on Bearings

During equipment cleaning:

• Avoid directing water jets toward bearings.
• Protect lubrication points.
• Check seals after cleaning.

4. Increase Inspection Frequency

For wet operating conditions, regularly monitor:

• Grease condition
• Bearing temperature
• Vibration
• Corrosion signs

Recommended Water Resistant Grease Selection Guide

Frequently Asked Questions

Does all grease resist water?

No. Different grease formulations have different levels of water resistance. Lithium complex, calcium sulfonate complex, and specially formulated greases generally provide better water resistance than standard greases.

Can water-contaminated grease continue to be used?

Generally not recommended. Water contamination may reduce lubrication performance and accelerate bearing damage. Contaminated grease should be removed and replaced.

How can I know if water has entered the bearing?

Common signs include:

• Milky grease appearance
• Rust formation
• Increased noise
• Higher vibration
• Temperature increase

Conclusion

Water washout is a major cause of bearing lubrication failure in wet industrial environments. Selecting a suitable water resistant grease, improving sealing protection, and maintaining proper lubrication practices can effectively reduce corrosion, wear, and unexpected equipment downtime.

For applications exposed to water, the correct grease selection is not only about lubrication performance but also about maintaining long-term equipment reliability.