D7 vs A7
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.
D7
Tool Steel
D7 combines maximum carbon and chromium with about 4% vanadium, giving the highest abrasive wear resistance of any conventional cold work steel. It is the last step before cemented carbide.
Standards: AISI D7
A7
Tool Steel
A7 packs very high carbon with about 4% vanadium, forming a dense population of hard vanadium carbides. It sits between D2 and the high-speed steels in abrasive wear resistance, for the most punishing cold-work applications.
Standards: DIN — (1.2431 family) · AISI A7 · GB Cr5Mo1V3 (near)
Chemical composition compared (%)
| Element | D7 | A7 |
|---|---|---|
| C | 2.15–2.50 | 2.00–2.85 |
| Si | 0.10–0.60 | ≤0.50 |
| Mn | 0.10–0.60 | 0.20–0.80 |
| Cr | 11.00–13.50 | 5.00–5.75 |
| Mo | 0.70–1.00 | 0.90–1.40 |
| V | 3.80–4.40 | 3.20–4.40 |
Properties compared
| Property | D7 | A7 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness (hardened) | 58–64 HRC | 58–64 HRC |
| Density | 7.70 g/cm³ | 7.80 g/cm³ |
| Wear resistance | Highest of the standard cold work steels | Extreme (vanadium carbides) |
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: D7 · A7. Substitution decisions for certified parts stay with the design authority.