SAE 52100 Bearing Steel
The American Standard for Absolute Endurance.
In the world of precision engineering, names matter. SAE 52100 is the American designation for the gold standard in bearing steel, renowned for its exceptional hardness, wear resistance, and fatigue life. It is a material born from a simple, uncompromising principle: when a component must endure millions of cycles under load, its failure is not a possibility—it is an inevitability that must be engineered against at a microscopic level.
The Science of Reliability
Extreme Through-Hardness
Hardens uniformly to an exceptional depth, achieving up to 64 HRC for maximum structural integrity.
Superior Wear Resistance
The high-carbon, chromoly chemistry creates an formidable defense against friction and abrasion.
Exceptional Fatigue Life
Engineered with a clean, homogenous microstructure to resist sub-surface failure over millions of stress cycles.
Excellent Dimensional Stability
Maintains precise shape and tolerances after heat treatment, essential for high-precision applications.
Technical Specifications
Chemical Composition
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.98 - 1.10 |
| Chromium (Cr) | 1.30 - 1.60 |
| Manganese (Mn) | 0.25 - 0.45 |
| Silicon (Si) | 0.15 - 0.35 |
Mechanical Properties (Hardened and Tempered, indicative only)
| Property | Value |
|---|---|
| Hardness | 60 - 64 HRC |
| Tensile Strength (MPa) | ~2050 |
| Yield Strength (MPa) | ~1800 |
Common Applications
Equivalent International Grades
| Standard | Grade |
|---|---|
| BS | EN31 |
| DIN / W-Nr. | 100Cr6 / 1.3505 |
| JIS | SUJ2 |
Similar & Alternative Grades:
SAE 52100 is the American standard for a class of steels also known as DIN 100Cr6 and JIS SUJ2.
Frequently Asked Questions about SAE 52100
Is SAE 52100 the same as EN31?
Yes, they are the direct international equivalents for the same high-carbon bearing steel. SAE 52100 is the American (AISI/SAE) designation, while EN31 is the British Standard designation. They have virtually identical chemical and mechanical properties and are used for the same applications.
Why is 52100 steel so popular for bearings?
Its popularity comes from its ability to be "through-hardened" to an exceptionally high hardness level (often over 60 HRC). This extreme hardness, combined with the material's inherent cleanliness and excellent fatigue strength, provides the superior performance needed to withstand millions of rotations under immense pressure.
Can you weld an SAE 52100 bright bar?
Welding SAE 52100 is not recommended. Its very high carbon content makes it extremely susceptible to cracking during and after welding. It is designed to be shaped in its soft, annealed state and then heat-treated for its final properties. Welding will destroy these properties and compromise the part's integrity.
A Microscopic Commitment to Perfection
The reliability of your most demanding machines is decided at a microscopic level—in the purity of the steel used for its bearings. The Marbrite Standard is our commitment to delivering an SAE 52100 round bar with a flawlessly clean, homogenous microstructure. We provide the perfect foundation, free from the inclusions that cause premature failure, so you can build components that are not just designed to perform, but engineered to outlast.