Professional Classification Perspective

From an industrial standpoint, Deep Groove Ball Bearings are generally divided into:

• Single Row Series (6000, 6200, 6300, 6400, etc.)

• Double Row Series (4200, 4300 series)

• Miniature Series (600, 620 series)

• Special Customized Designs

 

Components of Deep Groove Ball Bearings and Their Materials

1. Inner Ring

Function:
Mounted on the shaft and provides the raceway for rolling elements. Typical Materials:

• High carbon chromium bearing steel (GCr15 / AISI 52100):

  • Most commonly used

  • High hardness (HRC 60–64 after heat treatment)

  • Excellent fatigue resistance

• Stainless steel (AISI 440C):

  • Corrosion-resistant applications

• Carburized alloy steel (20CrMnTi):

  • Heavy-duty or impact-load applications

2. Outer Ring

Function:
Installed in the housing and forms the outer raceway.

Typical Materials:

• GCr15 / AISI 52100 bearing steel (standard industrial use)

• Stainless steel (440C) for humid or chemical environments

• High-temperature alloy steel for special thermal conditions

The outer ring material is typically identical to the inner ring to ensure matched hardness and fatigue performance.

3. Rolling Elements (Balls)

Function:
Reduce friction by enabling rolling contact between inner and outer rings.

Typical Materials:

• High carbon chromium steel balls (GCr15 / AISI 52100)

  • Precision ground for high roundness

  • Superior wear resistance

• Ceramic balls (Si₃N₄ – Silicon Nitride)

  • Used in hybrid bearings

  • Lightweight, high-speed capability

  • Electrically insulating

• Stainless steel balls (440C)

  • Corrosion-resistant environments

4. Cage (Retainer)

Function:
Maintains ball spacing and guides rolling elements during rotation.

Typical Materials:

• Pressed steel cage (low carbon steel):

  • Most economical and widely used

• Machined brass cage (HPb59-1 or similar):

  • High strength

  • Suitable for high-speed or heavy-duty applications

• Polyamide (Nylon PA66 + glass fiber):

  • Lightweight

  • Low noise

  • Ideal for electric motors

5. Seals or Shields (Optional)

Function:
Protect internal components from dust, contamination, and lubricant leakage.

Metal Shields (ZZ):

• Material: Cold-rolled steel

• Provide dust protection

• Suitable for high-speed operation

Rubber Seals (2RS):

• Material: NBR (Nitrile Rubber) bonded to steel reinforcement

• Offer better sealing performance

• Suitable for contaminated environments

For high-temperature applications, FKM (Viton) rubber may be used.

6. Lubricant (Grease or Oil)

Function:
Reduces friction, wear, and heat generation.

Typical Lubricants:

• Lithium-based grease (general industrial use)

• Polyurea grease (electric motor applications)

• Synthetic high-temperature grease

• Oil lubrication for high-speed precision use