9Cr18Mo — 9Cr18Mo Martensitic Stainless Steel — is a stainless steel supplied at HRC 58-62. Its chemistry centres on 0.95-1.20% carbon, 16.0-18.0% chromium and 0.40-0.60% molybdenum. Medical-grade stainless steel — wear resistance and corrosion resistance in one grade. 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 9Cr18Mo is, and where it fits
Grade selection is about matching the dominant failure mode. 9Cr18Mo's role in the range is clear: corrosion resistance with tool-steel 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)
- 9Cr18Mo / 95Cr18Mo
- AISI / ASTM (US)
- 440C / S44004
- JIS (Japan)
- SUS440C
- DIN / W-Nr (Germany)
- 1.4125 / X105CrMo17
- NF / AFNOR (France)
- Z100CD17
- UNI (Italy)
- X105CrMo17
- GOST (Russia)
- 95Kh18
Working hardness and what each band is for
9Cr18Mo 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 | 49 - 58 | Suitable for standard production tooling |
| Secondary range | 40 - 48 | Where the application calls for more toughness or more wear resistance |
| Annealed | 28 - 35 | Rough turning, Milling, Pre-heat treatment |
| Hardened | 58 - 62 | Medical-grade die tooling, Surgical instrument punches, Wear-resistant die components |
9Cr18Mo for hardened round bar and rotary dies
| Product line | Suitability | Working hardness | Typical applications |
|---|---|---|---|
| hardened round bar | Available but not first choice (3/5) | HRC 58-62 | Food-grade die-cutting blades, Medical surgical blades |
| custom rotary dies | Available but not first choice (3/5) | HRC 58-62 | Food-grade rotary dies, Medical packaging slitting rollers |
When to choose 9Cr18Mo — and when not to
| Choose 9Cr18Mo when… | Look at another grade when… |
|---|---|
| The die or blade contacts food, medical packaging or a wash-down environment | Maximum wear resistance is the priority — cobalt HSS or PM steel will outlast it |
| Corrosion staining on a standard tool steel has caused rejection or rework | Cost is the primary constraint and corrosion is not a real risk |
| You need HRC 58-62 and reasonable wear resistance in a stainless grade | Very high impact loads are present; stainless tool steels are less forgiving |
Related grades and guides for 9Cr18Mo
9Cr18Mo FAQ
9Cr18Mo (9Cr18Mo Martensitic Stainless Steel) is used for medical-grade, wear-resistant, corrosion-resistant applications. Medical-grade stainless steel — wear resistance and corrosion resistance in one grade In practice it is supplied as hardened round bar for die making and as machined rotary die bodies, at HRC 58-62 in normal production.