W2Mo9Cr4VCo8 — W2Mo9Cr4VCo8 High-Cobalt High-Speed Steel — is a high-cobalt high-speed steel supplied at HRC 65-66. Its chemistry centres on 1.05-1.15% carbon, 3.50-4.50% chromium, 9.00-10.00% molybdenum, 0.95-1.35% vanadium and 7.50-8.50% cobalt. 8% cobalt content — ultra-high hardness. It is available from stock as precision-ground hardened round bar from Φ2 to Φ100 mm, and as machined rotary die bodies made to drawing.
What W2Mo9Cr4VCo8 is, and where it fits
Grade selection is about matching the dominant failure mode. W2Mo9Cr4VCo8's role in the range is clear: maximum wear resistance at high hardness. If your dies fail by gradual wear, prioritise wear resistance. If they chip or crack, prioritise toughness — which usually means accepting a slightly lower hardness.
- GB (China)
- W2Mo9Cr4VCo8
- AISI / ASTM (US)
- M42 / T11342
- JIS (Japan)
- SKH59
- DIN / W-Nr (Germany)
- 1.3247 / HS2-9-1-8
- NF / AFNOR (France)
- HS2-9-1-8
- UNI (Italy)
- HS2-9-1-8
Working hardness and what each band is for
W2Mo9Cr4VCo8 hardens across a wide window, and the hardness you choose changes the tool's behaviour more than the grade does. Higher hardness buys wear resistance and edge retention at the cost of toughness; lower hardness does the reverse.
| Band | Hardness | Typical use |
|---|---|---|
| Primary working range | 65 - 66 | First choice for standard production tooling |
| Secondary range | 62 - 65 | Where the application calls for more toughness or more wear resistance |
W2Mo9Cr4VCo8 for hardened round bar and rotary dies
| Product line | Suitability | Working hardness | Typical applications |
|---|---|---|---|
| hardened round bar | Recommended (5/5) | HRC 65-66 | Ultra-high-hardness dies, High-temperature dies, Precision circular blades |
| custom rotary dies | Recommended (5/5) | HRC 65-66 | High-precision rotary dies, Thin-metal slitting rollers, High-temperature die rollers |
When to choose W2Mo9Cr4VCo8 — and when not to
| Choose W2Mo9Cr4VCo8 when… | Look at another grade when… |
|---|---|
| Abrasive or metallised film is being slit at high speed | The die fails by micro-chipping at the edge — PM23 is the correct answer |
| Thick board, honeycomb or mineral-filled stock is being cut | Impact loading is present; W2Mo9Cr4VCo8 has the lowest toughness of the three HSS grades |
| Edge wear is gradual and predictable, and you want the longest interval possible |
Related grades and guides for W2Mo9Cr4VCo8
W2Mo9Cr4VCo8 FAQ
W2Mo9Cr4VCo8 (W2Mo9Cr4VCo8 High-Cobalt High-Speed Steel) is used for ultra-high hardness, top wear resistance, high-temperature stable applications. 8% cobalt content — ultra-high hardness In practice it is supplied as hardened round bar for die making and as machined rotary die bodies, at 65-66 in normal production.