A2 vs D2
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.
A2
Tool Steel
A2 is an air-hardening 5% chromium cold work steel with much better toughness than D2 and far less distortion than oil-hardening grades. It is the default upgrade from O1 where die size or intricate shapes make quench cracking a risk.
Standards: DIN 1.2363 · AISI A2 · JIS SKD12 · GB Cr5Mo1V
D2
Tool Steel
D2 is the world-standard high-carbon, high-chromium cold work tool steel. Massive chromium carbides give exceptional abrasive wear resistance and long die life in blanking and forming.
Standards: DIN 1.2379 · AISI D2 · JIS SKD11 · GB Cr12Mo1V1
Chemical composition compared (%)
| Element | A2 | D2 |
|---|---|---|
| C | 0.95–1.05 | 1.45–1.60 |
| Si | 0.10–0.50 | 0.10–0.60 |
| Mn | 0.40–1.00 | 0.20–0.60 |
| Cr | 4.75–5.50 | 11.00–13.00 |
| Mo | 0.90–1.40 | 0.70–1.00 |
| V | 0.15–0.50 | 0.70–1.00 |
Properties compared
| Property | A2 | D2 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness (hardened) | 57–62 HRC | 58–62 HRC |
| Density | 7.85 g/cm³ | 7.70 g/cm³ |
| Toughness | Good for cold work | — |
| Wear resistance | — | Very high |
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: A2 · D2. Substitution decisions for certified parts stay with the design authority.