Fatigue spalling is one of the most critical and often misunderstood failure modes in sliding bearings, especially in applications involving high loads, oscillatory motion, linear motion, and harsh working environments. Unlike abrasive wear or corrosion, fatigue spalling develops internally and may remain undetected until severe surface damage occurs.
For OEMs, maintenance engineers, and industrial buyers in Europe, North America, and the Middle East, understanding the root causes of fatigue spalling—and how to prevent it—is essential to improving equipment reliability, extending bearing service life, and reducing total cost of ownership.
This article explains why fatigue spalling occurs in sliding bearings, how to recognize early warning signs, and what practical engineering solutions can effectively prevent it.
What Is Fatigue Spalling in Sliding Bearings?
Fatigue spalling refers to the progressive flaking or pitting of a bearing’s sliding surface caused by repeated cyclic stresses exceeding the material’s fatigue limit. Over time, micro-cracks form beneath the surface, propagate, and eventually cause small fragments of material to detach.
Unlike rolling bearings, sliding bearings often operate under:
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Boundary or mixed lubrication
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High surface pressures
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Repeated load reversals
These conditions make fatigue-related failures particularly relevant.
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Main Causes of Fatigue Spalling in Sliding Bearings
1. Excessive Contact Stress
When actual contact stress exceeds the fatigue strength of the bearing material, subsurface cracks begin to develop. This commonly occurs due to:
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Under-designed bearing size
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Unexpected load peaks
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Shock loads in oscillatory motion
Applications such as construction machinery, mining equipment, and hydraulic systems are especially vulnerable.
2. Inadequate Bearing Material Selection
Different sliding bearing materials exhibit vastly different fatigue resistance. Using a general-purpose material in a high-load or oscillating application often leads to early spalling.
Common risk scenarios include:
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Soft overlays under high pressure
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Polymer liners exceeding temperature limits
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Metal-backed bearings without proper fatigue-rated layers
3. Poor Lubrication Conditions
Fatigue spalling is accelerated when bearings operate under boundary lubrication for extended periods. Insufficient lubricant film thickness results in:
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Metal-to-material contact
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Stress concentration at asperities
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Rapid crack initiation
This is especially common in:
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Start-stop cycles
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Oscillatory motion with small angles
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Low-speed, high-load applications
4. Misalignment and Edge Loading
Even slight misalignment can cause edge loading, dramatically increasing localized stress. Over time, this leads to fatigue cracks at the most heavily loaded zones of the bearing surface.
Precision alignment and proper housing design are often underestimated but play a crucial role in fatigue life.
5. Elevated Temperatures
High temperatures reduce material fatigue strength and accelerate lubricant degradation. In industries such as steel processing, energy, and heavy manufacturing, temperature-related fatigue spalling is a frequent failure mode.
Typical Signs of Fatigue Spalling
Early detection is key. Common indicators include:
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Small surface pits or flaking
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Gradual increase in noise or vibration
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Metallic debris in lubricant
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Declining motion accuracy
Once visible spalling appears, bearing replacement is usually unavoidable.
Practical Solutions to Prevent Fatigue Spalling
1. Select Fatigue-Optimized Bearing Materials
Preventing fatigue spalling starts with correct material engineering. High-performance sliding bearings should offer:
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High load-bearing capacity
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Excellent fatigue resistance
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Stable properties under temperature and load cycling
CNEPEN provides engineered sliding bearing solutions tailored to demanding load and motion profiles rather than generic catalog designs.
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2. Optimize Bearing Design and Load Distribution
Key design strategies include:
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Increasing bearing projected area
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Avoiding sharp housing edges
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Using chamfers to reduce stress concentration
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Ensuring proper shaft hardness and surface finish
Early collaboration with an experienced bearing manufacturer significantly reduces fatigue-related risks.
3. Improve Lubrication Strategy
Depending on the application, fatigue life can be extended by:
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Selecting higher-viscosity lubricants
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Using solid-lubricant-based self-lubricating bearings
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Ensuring consistent lubricant supply in oscillatory motion
4. Control Alignment and Installation Accuracy
Precision installation minimizes edge loading. Recommended actions include:
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Tight control of housing tolerances
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Shaft alignment checks
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Avoiding press-fit distortion
Even the best bearing material cannot compensate for poor installation practices.
5. Use Condition Monitoring in Critical Systems
In high-value equipment, monitoring techniques such as vibration analysis and oil debris analysis help identify fatigue damage before catastrophic failure occurs.
Why Global OEMs Choose CNEPEN Sliding Bearings
For customers serving European, North American, and Middle Eastern markets, CNEPEN offers:
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Application-engineered sliding bearing solutions
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Proven fatigue-resistant materials
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Support for oscillatory, linear, and high-temperature applications
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Consistent quality for global supply chains
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https://www.cnepen.com/contact-us
Conclusion
Fatigue spalling in sliding bearings is not a random failure—it is the result of load, material, lubrication, and design interactions. By understanding the causes and applying proven prevention strategies, engineers can significantly extend bearing service life and improve equipment reliability.
For demanding applications where fatigue resistance is critical, partnering with an experienced sliding bearing manufacturer like CNEPEN ensures not only reliable products, but also long-term engineering confidence.
FAQs
How often should sliding bearings be checked for fatigue spalling?
How often inspections are done depends on how bad the operation and the weather are. For applications that aren't as demanding, the inspection period can be stretched to 12–18 months, but for heavy-duty applications, it should be inspected every 6–12 months. Condition monitoring systems can keep an eye on things and let you know right away if there is a problem.
Can lubrication alone stop fatigue spalling in sliding bearings?
Spalling can be greatly reduced by properly lubricating, but this alone can't stop it from happening. Other things must be taken into account as well. For spalling prevention to work, material choice, design optimization, operational control, and lubrication management must all work together.
What credentials should I look for in sliding bearing suppliers that I can trust?
ISO 9001 quality management certification shows that the way things are made is always the same. They confirm the makeup and properties of a material. When someone sees that you meet marine, automotive, aerospace, or other specific standards, they know you have the specialized skills needed for those tough situations.
Partner with Epen for Superior Bearing Performance
To get reliable bearing performance, you need to work with a sliding bearings manufacturer that knows a lot about spalling prevention. Epen's high-tech engineering skills and wide range of products offer solutions that are customized for your needs. Our technical team gives expert advice on choosing materials, making designs better, and planning maintenance that keeps bearings working for as long as possible and lowers the cost of running the business.
See how quality engineering can prevent fatigue spalling and make your equipment more reliable. Our network of sliding bearings suppliers makes sure that standard and custom bearing solutions are always available at a fair price. To talk about your unique bearing needs and learn how our successful options can improve the performance of your equipment, email us at epen@cnepen.cn. Go to cn-epen.com to see all of our products and technical resources that are meant to help you succeed.
References
Johnson, R.M. (2019). "Fatigue Mechanisms in Plain Bearing Systems." Journal of Tribology Engineering, Volume 45, Issue 3, pages 234-251.
Smith, A.K. and Williams, P.J. (2020). "Material Selection Criteria for High-Load Sliding Bearings." International Conference on Bearing Technology Proceedings, pages 78-95.
Brown, D.L. (2018). "Lubrication Effects on Surface Fatigue in Plain Bearings." Tribology International Research, Volume 112, pages 445-462.
Chen, H.X. and Davis, M.R. (2021). "Stress Analysis and Spalling Prevention in Industrial Bearing Applications." Mechanical Engineering Design Journal, Volume 28, Issue 7, pages 189-206.
Thompson, K.E. (2017). "Condition Monitoring Strategies for Early Spalling Detection." Maintenance and Reliability Engineering, Volume 39, Issue 12, pages 567-584.
Garcia, L.M. and Anderson, J.P. (2022). "Advanced Materials for Fatigue-Resistant Bearing Applications." Materials Science and Engineering Review, Volume 156, pages 234-259.
