M35 vs M42
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.
M35
Tool Steel
M35 is M2 with about 5% cobalt added, the most popular cobalt high-speed steel worldwide. The cobalt raises red hardness so tools keep cutting at the higher speeds and feeds used on stainless and alloy steels.
Standards: DIN 1.3243 · AISI M35 · JIS SKH55 · GB W6Mo5Cr4V2Co5
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
Chemical composition compared (%)
| Element | M35 | M42 |
|---|---|---|
| C | 0.87–0.95 | 1.05–1.15 |
| Si | ≤0.45 | ≤0.45 |
| Mn | ≤0.40 | ≤0.40 |
| Cr | 3.75–4.50 | 3.50–4.25 |
| Mo | 4.70–5.20 | 9.00–10.00 |
| W | 5.90–6.70 | 1.15–1.85 |
| V | 1.70–2.10 | 0.85–1.25 |
| Co | 4.50–5.00 | 7.75–8.75 |
Properties compared
| Property | M35 | M42 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness (hardened) | 63–66 HRC | 67–70 HRC |
| Density | 8.10 g/cm³ | 7.90 g/cm³ |
| Red hardness | Higher than M2 (5% cobalt) | Excellent — top of the conventional HSS range |
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: M35 · M42. Substitution decisions for certified parts stay with the design authority.