M50 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.
M50
Tool Steel
M50 is a molybdenum high-speed steel developed for rolling bearings in jet engines, where it keeps hardness and fatigue life at operating temperatures near 300 °C. It is also used for high-performance cutting tools.
Standards: AISI M50
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 | M50 | M2 |
|---|---|---|
| C | 0.77–0.85 | 0.78–0.88 |
| Si | ≤0.60 | ≤0.45 |
| Mn | ≤0.45 | ≤0.40 |
| Cr | 3.75–4.50 | 3.80–4.50 |
| Mo | 4.00–4.75 | 4.70–5.20 |
| V | 0.80–1.25 | 1.70–2.10 |
| W | — | 5.90–6.70 |
Properties compared
| Property | M50 | M2 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness (hardened) | 61–64 HRC | 63–66 HRC |
| Density | 7.90 g/cm³ | 8.10 g/cm³ |
| Fatigue performance | High — bearing-grade cleanliness specified | — |
| Red hardness | — | 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: M50 · M2. Substitution decisions for certified parts stay with the design authority.