O6 vs O1
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
O6
Tool Steel
O6 is a graphitic oil-hardening tool steel: free graphite particles in its microstructure act as a solid lubricant. It resists galling and seizing in sliding contact better than any other tool steel class.
Standards: AISI O6
O1
Tool Steel
O1 is a general-purpose oil-hardening tool steel — cheap, easy to heat treat with basic equipment, and dimensionally stable enough for short-run tooling.
Standards: DIN 1.2510 · AISI O1 · JIS SKS3 · GB 9CrWMn
Chemical composition compared (%)
| Element | O6 | O1 |
|---|---|---|
| C | 1.25–1.55 | 0.85–0.95 |
| Si | 0.55–1.20 | 0.10–0.40 |
| Mn | 0.30–1.10 | 1.00–1.20 |
| Mo | 0.20–0.40 | — |
| Cr | — | 0.50–0.70 |
| W | — | 0.50–0.70 |
| V | — | 0.05–0.15 |
Properties compared
| Property | O6 | O1 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness (hardened) | 55–60 HRC | 57–62 HRC |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
| Self-lubrication | Graphite in microstructure | — |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: O6 · O1. Substitution decisions for certified parts stay with the design authority.