How to Choose Bearings for High-Speed Applications: A Comprehensive Guide（III）

1. Recap from Part II – Quick overview of types and basic concepts

2. Advanced Precision Grades – P4, P2; why precision matters at ultra-high speeds

3. Hybrid Ceramic vs Full Steel – Performance benefits, weight, thermal properties

4. Tolerance & Fit Requirements – Shaft/bore fits, bearing clearance, thermal expansion

5. Mounting Methods & Preload Settings – Techniques like tapered sleeve, hydraulic mounting

6. Lubrication Strategy Refinement – Additives, grease regimens for high rpm

7. Vibration & Noise Control – Design choices to minimize harmonic resonance

8. Case Applications – Precision spindles, aerospace, medical equipment

9. DSBR’s Custom Support – Offering precise tuning, lab verification, packaging for OEMs

10. Conclusion – Final advice + linking to parts I & II and DSBR’s consulting services

Chapter 5: Material Considerations in High-Speed Bearings

    The materials used in high-speed bearings significantly influence their performance, durability, and safety under extreme operating conditions. To achieve high rotational speeds while maintaining minimal wear and precise operation, every component of the bearing—rings, rolling elements, and cages—must be made from materials chosen for their thermal stability, strength, and low mass.

5.1 Bearing Ring Materials: High-Quality Steels

The most common steel used in high-speed bearing rings is GCr15 (equivalent to AISI 52100), a high-carbon chromium steel known for:

• High hardness (≥ HRC 60–65 after heat treatment)

• Excellent fatigue strength

• Dimensional stability

• Good polishability and roundness retention

For ultra-high-speed or high-temperature environments, manufacturers may opt for:

• Vacuum degassed steel (e.g., VIM-VAR 52100): reduced impurities, better fatigue resistance

• Stainless steel (AISI 440C or 304): for environments prone to corrosion or exposure to chemicals

• Carburized steel (e.g., SAE 8620): offering higher core toughness and impact resistance

 DSBR uses GCr15 bearing steel with optimized microstructure control, ensuring uniform hardness and crack resistance even under shock loads.

5.2 Rolling Element Materials: Ceramic vs. Steel

The choice of rolling element materials has a direct effect on limiting speed, friction, and temperature stability.

✅ Steel Balls/Rollers:

• Heavier, which increases centrifugal force at high RPM

• Conduct heat and electricity

• Lower cost, common in general-purpose applications

✅ Ceramic Balls (e.g., Silicon Nitride Si₃N₄):

• 60% lighter than steel → less centrifugal force

• 50% harder than steel → higher wear resistance

• Electrically insulating → prevent electric arcing in motors

• Non-corrosive and chemically stable

 Ceramic hybrid bearings (steel rings + ceramic balls) are the preferred choice in electric spindles, high-speed dental tools, and EV drive motors.

5.3 Cage Materials: Strength + Low Friction

The bearing cage (retainer) guides the rolling elements and prevents collision. In high-speed systems, cage design and material influence:

• Friction

• Lubricant flow

• Operating temperature

• Vibration resistance

Common Cage Materials:

✅ Summary:

The success of a high-speed bearing begins at the material level. While steel is still dominant for most components, the integration of ceramic elements and advanced polymers has pushed the performance envelope. Material synergy—where each part complements the others in thermal, mechanical, and chemical behavior—is the key to achieving long service life and operational reliability.

DSBR Materials Advantage:
We offer a wide range of materials certified by metallurgical reports, with in-house spectrometer and hardness testing. Whether you need ceramic hybrids, stainless solutions, or custom cages, our engineering team delivers OEM-grade precision with batch consistency.

Chapter 6: Lubrication in High-Speed Bearings

Lubrication is a critical factor in the performance and lifespan of high-speed bearings. At elevated rotational speeds, friction and heat generation increase exponentially. A well-chosen lubrication strategy reduces contact stress, dissipates heat, prevents metal-to-metal contact, and protects against contaminants.

6.1 The Role of Lubrication in High-Speed Bearings

Proper lubrication helps in:

• ✅ Minimizing friction and wear

• ✅ Reducing heat buildup

• ✅ Protecting against corrosion and contaminants

• ✅ Extending lubricant and bearing service life

Without appropriate lubrication, high-speed bearings may fail prematurely due to:

• Grease degradation

• Excessive heat

• Dry contact between rolling elements and raceways

• Oxidation and material fatigue

6.2 Grease vs. Oil Lubrication: Which Is Better?

Grease Lubrication

Grease is commonly used in sealed bearings and applications where simplicity and maintenance-free operation are preferred.

Advantages:

• Easy to apply

• Seals retain grease and prevent contamination

• Lower leakage risk

Limitations in High-Speed Settings:

• Generates higher friction at very high speeds

• Thermal resistance is limited

• May require specialized low-friction or synthetic greases

Grease is ideal when:

• DN value ≤ 300,000

• Moderate speed and temperature

• Space constraints prevent circulating oil systems

Oil Lubrication

Oil is preferred in ultra-high-speed applications and open systems where thermal management is crucial.

Common Oil Methods:

• Oil bath: Simple but not suitable for very high speeds

• Oil-mist: Atomized oil droplets suspended in air

• Oil-air: Precise air/oil mix injected at intervals

• Oil jet: High-pressure stream aimed directly at contact zone

Benefits:

• Efficient cooling

• Lower friction

• Continuous lubrication and cleaning effect

Tip: For DN values ≥ 500,000, use oil-air or oil-mist systems to prevent overheating and lubricant starvation.

6.3 Choosing the Right Lubricant

When selecting lubricants, consider:

• Viscosity: Low enough to reduce friction, high enough to maintain film

• Base Oil Type: Mineral vs. synthetic (e.g., PAO for longer life)

• Additives: EP (extreme pressure), anti-oxidants, corrosion inhibitors

• Operating Temperature Range: High-temp greases use thickening agents like lithium complex or PTFE

• Compatibility: Ensure compatibility with seal materials and cage polymers

6.4 Lubrication Maintenance Best Practices

• Follow re-lubrication intervals based on RPM, load, and environment

• Use automatic lubricators for consistency in high-speed spindles

• Avoid over-lubrication, which can cause heat buildup

• Monitor temperature and vibration to detect lubrication-related issues early

• Store lubricants properly to avoid moisture and degradation

✅ Summary:

In high-speed bearing systems, lubrication is not just a routine step—it is a core engineering decision. The wrong lubricant or delivery method can lead to rapid failure, even if the bearing is correctly designed. Understanding your application’s speed, temperature, and load will help determine whether grease, oil-air, or oil-mist systems are the best fit.

DSBR Lubrication Support
We offer lubrication consultation services as part of our OEM package. From low-friction greases to full oil-air integration, DSBR can supply bearings pre-lubricated, sealed, or with customer-specified grease brands (e.g., Mobil, Klüber, Shell). Our team helps you optimize bearing life while reducing downtime.