ISO M — Stainless Steel · M01
M01 — Austenitic (304, 316L)
Hardness range: 150–220 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 — M01
- ISO designation
- M01 (ISO M — Stainless Steel)
- Material
- Austenitic (304, 316L)
- Hardness
- 150–220 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 304 / 316L — starting point
- ISO application class
- M (stainless). Match the insert's ISO class, not the brand name: an M15–M25 grade is the brand-independent common denominator. Sandvik, Kennametal, Iscar, Walter, Seco and Mitsubishi each publish an M-class grade for 304/316L — pick by ISO class, then confirm the exact grade for your condition.
- Grade & coating
- Tough PVD-coated carbide. Roughing ≈ M25–M30 for heat and edge security; finishing ≈ M10–M20 for a sharper edge and better surface.
- Geometry
- Positive rake, sharp or lightly honed edge, open polished chipbreaker. Avoid a heavy negative land or chamfer — it pushes the material and accelerates work-hardening.
- Starting parameters (carbide)
- Vc ≈ 120–200 m/min, fn ≈ 0.10–0.35 mm/rev, high-pressure coolant 15–20 bar aimed at the edge. Typical starting band — confirm in the advisor or on a sample part before production.
304 / 316L: what goes wrong, and what to check first
- Built-up edge
- Smeared finish and sudden chipping usually mean cutting speed too low, or the edge dwelling in the cut. Raise Vc into the working band, switch to a sharper positive polished edge, and get coolant to the edge. See the tool-wear guide.
- Work-hardened skin
- Rapid flank wear and re-cutting come from an inconsistent depth of cut, or the tool stopping in cut and leaving a hardened ramp the next pass re-cuts. Keep DOC above the previously hardened layer and never let the tool dwell.
- Notch wear at the DOC line
- Oxidation and abrasion concentrate at the depth-of-cut line on austenitics. Vary DOC slightly between passes, ease Vc back, and use a tougher edge grade.
- Long gummy chips
- Feed too low for the chipbreaker to engage. Increase fn into the band above — controlled chips, not lower speed, is usually the fix.
Reference data
Insert grade index
ISO insert-code index
CNMG120408 — general turning
CCMT09T304 — positive finishing
Tool-wear diagnosis
Get cutting parameters for Austenitic (304, 316L)
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