52100 Steel
A high-carbon chromium bearing steel
Typical values for the temper in the title
52100 contains about 1% carbon and about 1.5% chromium. After hardening and a low temper it reaches 60–65 HRC, with very high wear and rolling-contact fatigue resistance, which is what bearings require: balls and rollers pressed again and again against the rings.
The special requirement in bearings is cleanliness: small inclusions in the material are starting points for fatigue cracks. So bearing steel is produced by processes that reduce inclusions and is defined in dedicated standards (ASTM A295, EN ISO 683-17). It is also used for tools, gauges and knives.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Modulus of elasticity E | 210 GPa | |
| Density ρ | 7.83 g/cm³ | |
| Hardness | 60–65 HRC (hardened) | depends on heat treatment |
| Machinability | 55% | relative rating in the site database |
Chemical composition (wt %)
| Element | Range | Role |
|---|---|---|
| C carbon | 0.98–1.10 | hardness |
| Cr chromium | 1.30–1.60 | hardenability and wear resistance |
| Mn manganese | 0.25–0.45 | |
| Si silicon | 0.15–0.35 | |
| Fe iron | balance |
Ranges per SAE J404 and ASTM A322. P max 0.035, S max 0.040. Equivalents in other standards are close in composition, not identical.
Conditions and heat treatment
In alloy steels, chromium, molybdenum and nickel raise hardenability: thicker parts reach full hardness even at the center. Properties are set mainly by heat treatment.
| Condition | Properties | When to choose it |
|---|---|---|
| Spheroidize annealed | soft, for machining | delivery condition |
| Hardened, low temper | 60–65 HRC | bearings and tools |
Applications
- Bearing balls and rollers
- Bearing rings
- Gauges and tools
- Shafts for rolling contact
- Knives
Fabrication
Heat treatment
Oil quenched from a moderate temperature and tempered low. Deep cooling is sometimes added, to reduce retained austenite and improve dimensional stability.
Processing
Machine spheroidized, grind after hardening.
Welding
Not suited to welding.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| 440C | 760–1900 / 450–1860 MPa | Not recommended | a stainless bearing steel, corrosion resistant · material page |
| 1095 | 830–1050 / 480–620 MPa | Difficult — Preheat 250C | a high-carbon steel, without chromium · material page |
| 8620 | 530–620 / 385–415 MPa | Good | a carburized steel for large bearings · material page |
Common mistakes
Using 52100 unprotected in a humid environment
It is not corrosion resistant. For such an environment, 440C.
Ordering a "similar" steel without cleanliness requirements
In bearings, cleanliness governs fatigue life.
Welding
The high carbon causes cracking.
Equivalents, standards and supply
| EN | 100Cr6 (1.3505) |
|---|---|
| JIS | SUJ2 |
| Standards | ASTM A295 / EN ISO 683-17 |
| Forms | rod · wire · pipe |
| Producers | SKF Steel · Ovako · Sanyo Special Steel |
Learn more
Values are typical and for comparison only, and depend strongly on condition and diameter. For design, rely on the standard and on the mill certificate. Sources: SAE J403 and J404, ASTM A29, A322 and A519 (composition), producer data sheets, and the METAL HUB materials database.
Updated: October 31, 2026