M42 vs M2
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.
M42
Tool Steel
M42 is a molybdenum-cobalt high-speed steel reaching 67–70 HRC, the hardest of the widely stocked conventional HSS grades. It cuts hardened steels, superalloys and other materials that destroy M2 tooling.
Standards: DIN 1.3247 · AISI M42 · JIS SKH59 · GB W2Mo10Cr4VCo8
M2
Tool Steel
M2 is the most widely used high-speed steel in the world, balancing red hardness, toughness and cost for cutting tools of every kind.
Standards: DIN 1.3343 · AISI M2 · JIS SKH51 · GB W6Mo5Cr4V2
Chemical composition compared (%)
| Element | M42 | M2 |
|---|---|---|
| C | 1.05–1.15 | 0.78–0.88 |
| Si | ≤0.45 | ≤0.45 |
| Mn | ≤0.40 | ≤0.40 |
| Cr | 3.50–4.25 | 3.80–4.50 |
| Mo | 9.00–10.00 | 4.70–5.20 |
| W | 1.15–1.85 | 5.90–6.70 |
| V | 0.85–1.25 | 1.70–2.10 |
| Co | 7.75–8.75 | — |
Properties compared
| Property | M42 | M2 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness (hardened) | 67–70 HRC | 63–66 HRC |
| Density | 7.90 g/cm³ | 8.10 g/cm³ |
| Red hardness | Excellent — top of the conventional HSS range | To ~600 °C |
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: M42 · M2. Substitution decisions for certified parts stay with the design authority.