ISO M — Stainless Steel · M10
M10 — Duplex stainless
Hardness range: 240–300 HB. Part of the ISO M — Stainless Steel group. Stainless steel presents work-hardening as the main challenge. Austenitic grades (304, 316L) built-up-edge and notch-wear rapidly. Positive, sharp geometry with high-pressure coolant at 15–20 bar is standard. Consistent depth of cut prevents re-cutting the hardened chip ramp.
Material profile — M10
- ISO designation
- M10 (ISO M — Stainless Steel)
- Material
- Duplex stainless
- Hardness
- 240–300 HB
- ISO group colour
- Stainless Steel
Tooling guidance — M-group
- Group summary
- Work hardening is the main challenge. Sharp positive geometry, high-pressure coolant 15–20 bar, consistent DOC.
Insert selection for duplex stainless (2205 / 2507) — starting point
- ISO application class
- M (stainless). Match the insert's ISO class, not the brand name. Sandvik, Kennametal, Iscar, Walter, Seco and Mitsubishi each publish an M-class grade — pick by ISO class, then confirm the exact grade for your condition.
- Grade & coating
- Tough PVD-coated carbide, a robust M-class grade. Duplex (2205 / 2507) is stronger and work-hardens harder than austenitic 304 / 316, so favour edge security over a keen finishing edge.
- Geometry
- Positive but robust honed edge, and a rigid setup — duplex generates high cutting forces. High-pressure coolant 15–20 bar.
- Starting parameters
- Vc ≈ 80–150 m/min (lower than 304 / 316 — duplex runs slower), fn ≈ 0.10–0.30 mm/rev. Typical starting band — confirm in the advisor or on a sample part.
Selection table: duplex stainless (2205 / 2507)
| Operation | Geometry | ISO class | Coating family | Coolant | First check |
|---|---|---|---|---|---|
| Roughing | Positive but robust honed edge; rigid setup for high cutting forces | M (robust M-class grade) | Tough PVD-coated carbide | High-pressure coolant 15–20 bar | Severe work-hardening: keep DOC above the hardened layer |
| Finishing | Positive, sharp but robust edge | M (robust M-class grade) | PVD-coated carbide | High-pressure coolant 15–20 bar | Built-up edge at low speed: raise Vc into the duplex band |
| Interrupted cut | Robust honed edge | M (tougher M-class grade) | Tough PVD-coated carbide | High-pressure coolant 15–20 bar | Notch wear at the depth-of-cut line: vary DOC |
| Low rigidity / thin wall | Robust positive edge; shorten overhang, clamp rigidly | M (robust M-class grade) | PVD-coated carbide | High-pressure coolant 15–20 bar | Deflection and chatter: duplex pushes back |
duplex stainless (2205 / 2507): what goes wrong, and what to check first
- Severe work-hardening
- Worse than austenitic stainless. Keep DOC above the previously hardened layer, never let the tool dwell, and use a sharp but robust edge. See the tool-wear guide.
- High cutting forces and deflection
- Duplex is strong and pushes back. Shorten overhang, clamp rigidly, and use a robust edge to avoid deflection and chatter.
- Notch wear at the depth-of-cut line
- Vary the depth of cut between passes, ease Vc, and use a tougher grade.
- Built-up edge at low speed
- Raise Vc into the (lower) duplex band and aim coolant at the edge.
Reference data
Frequently asked questions
What insert should I use for duplex stainless 2205 / 2507?
A tough M-class PVD-coated carbide with a robust positive edge. Match the ISO M class across brands rather than the brand name and confirm the exact grade in the advisor.
Why is duplex harder to machine than 316?
Duplex is stronger and work-hardens more, generating higher cutting forces and heat. Run a lower speed band, a robust edge, and a rigid setup.
What cutting speed for duplex 2205 with carbide?
Roughly Vc 80–150 m/min and fn 0.10–0.30 mm/rev with high-pressure coolant — lower than austenitic stainless. Treat this as a starting band and confirm on a sample part.
How do I stop work-hardening in duplex?
Keep the depth of cut above the hardened layer, never let the tool dwell, and use a sharp robust edge with adequate speed.
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Grade designations in this group
Each page cross-references the EN, Werkstoffnummer, AISI/UNS and JIS designations for one material, with the ISO machining group it falls in.
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