M50
Data under reviewM50 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.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.77–0.85 |
| Si | ≤0.60 |
| Mn | ≤0.45 |
| Cr | 3.75–4.50 |
| Mo | 4.00–4.75 |
| V | 0.80–1.25 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Delivery condition | Annealed |
| Hardness (hardened) | 61–64 HRC |
| Density | 7.90 g/cm³ |
| Fatigue performance | High — bearing-grade cleanliness specified |
Heat treatment
Preheat 845 °C; harden 1175–1205 °C; triple temper 540–560 °C.
Equivalent grades
| Standard | Designation |
|---|---|
| aisi | M50 |
Compare side by side: M50 vs M1 · M50 vs M2
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Aircraft engine bearings, high-temperature ball and roller bearings, drills and end mills.
Processing: Supplied to strict cleanliness (vacuum-melted) specifications for bearing duty; heat treatment follows HSS practice.
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Ask for a quotationVisit NasteelSource: ASTM A600 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.