Core Materials for Chinese Bearing Rings: A Simple Guide

Choosing the right material for bearing rings is crucial for performance and durability. Here’s a straightforward guide to common materials used in Chinese bearing rings.

1. High-Carbon Chromium Steel (e.g., GCr15)

Key Features:

• Hardness: Contains about 1% carbon and 1.5% chromium, reaching HRC 60–64 after heat treatment.
• Fatigue Resistance: Low sulfur and phosphorus content extends service life.
• Corrosion Resistance: Chromium forms a protective oxide layer.

Applications:

Used in 90% of general-purpose bearings, such as:

• Deep groove ball bearings
• Angular contact bearings
• Machinery, motors, and automotive parts

Standards:

Complies with GB/T 18254, the Chinese national standard.

2. Stainless Steel (e.g., 9Cr18 / AISI 440C)

Key Features:

• Corrosion Resistance: Contains ≥17% chromium, ideal for wet or corrosive environments.
• Heat Resistance: Reliable up to 300°C.

Applications:

Suitable for:

• Food processing equipment
• Chemical machinery
• Medical devices

Limitations:

Slightly lower hardness (HRC 58–60) and load capacity compared to GCr15.

3. Carburized Steel (e.g., G20CrMo)

Key Features:

• Surface Hardening: Low-carbon core ensures toughness, while the surface reaches HRC 58–62 after carburization.
• Impact Resistance: Handles heavy shocks and vibrations well.

Applications:

Used in:

• Railway bearings
• Wind turbine gearboxes
• Heavy-load machinery

4. Specialized Materials (Ceramic Coatings, Nitrided Steel)

Innovations:

Ceramic-Coated Bearings:

• Coatings like zirconia (ZrO₂) or silicon carbide (SiC) reduce friction by up to 50%.
• Ideal for high-speed spindles and aerospace applications.

Nitrided Steel (e.g., 30CrMoAl):

• Surface hardness exceeds HV 1000 after nitriding.
• Suitable for temperatures up to 500°C.
• Used in turbochargers and high-heat environments.

5 Critical Performance Requirements

1. Fatigue Resistance: Prevents surface peeling under cyclic loads.
2. Wear Resistance: Minimizes precision loss over time.
3. High Hardness: Maintains shape under heavy loads.
4. Corrosion Resistance: Passes 48-hour salt spray test.
5. Machinability: Easy to cut and heat-treat.

Material Selection Tips

• Standard Use: Choose cost-effective GCr15 steel.
• Corrosive Environments: Opt for stainless steel (9Cr18) or chrome-plated bearings.
• Extreme Conditions: Use carburized steel for shock resistance or ceramic-coated bearings for high-speed/high-temperature applications.

Conclusion

Thanks to advanced manufacturing techniques like vacuum degassing and electroslag remelting, Chinese bearing rings now offer quality comparable to global brands. Selecting the right material ensures longer lifespan and better reliability.

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