ISO K — Cast Iron · K01
K01 — Grey cast iron (soft)
Hardness range: 180–220 HB. Part of the ISO K — Cast Iron group. Cast iron is abrasive and brittle — short chips, no built-up-edge. CVD alumina (Al₂O₃) coatings resist the high-temperature abrasion. Dry machining is acceptable for grey iron; coolant helps with nodular grades. Main failure mode: flank wear. High-speed machining is effective.
Material profile — K01
- ISO designation
- K01 (ISO K — Cast Iron)
- Material
- Grey cast iron (soft)
- Hardness
- 180–220 HB
- ISO group colour
- Cast Iron
Tooling guidance — K-group
- Group summary
- CVD alumina coatings excel. Dry machining acceptable for grey CI. Abrasive wear is the main failure mode.
Insert selection for grey cast iron — starting point
- ISO application class
- K (cast iron). Match the insert's ISO class, not the brand name. Sandvik, Kennametal, Iscar, Walter, Seco and Mitsubishi each publish a K-class grade — pick by ISO class, then confirm the exact grade for your condition.
- Grade & coating
- CVD alumina (Al₂O₃)-coated carbide, K10–K20 — alumina resists the high-temperature abrasion of grey iron. Ceramic for high-speed finishing.
- Geometry
- Negative geometry is fine and economical. Use a honed edge for cast skin and interrupted cuts. Grey iron makes short chips and no built-up edge, so chip control is easy.
- Starting parameters
- Vc ≈ 150–350 m/min, fn ≈ 0.10–0.50 mm/rev; dry is acceptable. Typical starting band — confirm in the advisor or on a sample part.
Selection table: grey cast iron
| Operation | Geometry | ISO class | Coating family | Coolant | First check |
|---|---|---|---|---|---|
| Roughing | Negative geometry, honed edge for cast skin | K10–K20 | CVD alumina (Al₂O₃)-coated carbide | Dry is acceptable | Abrasive flank wear: keep the speed sensible |
| Finishing | Negative geometry; short chips, no built-up edge | K10–K20 | CVD alumina carbide; ceramic for high-speed finishing | Dry is acceptable | Flank wear drifting the size |
| Interrupted cut | Honed edge for cast skin and interruptions | K10–K20 (tougher end) | CVD alumina carbide | Dry is acceptable | Edge chipping on skin; ease into the first cut |
| Low rigidity / thin wall | Negative geometry with a honed edge; support the part | K10–K20 | CVD alumina carbide | Dry is acceptable | Frittering at the cut exit: reduce feed at exit |
grey cast iron: what goes wrong, and what to check first
- Abrasive flank wear (the main mode)
- Free graphite and the matrix abrade the edge. Use a CVD-alumina K-grade and keep the speed sensible. See the tool-wear guide.
- Edge chipping on cast skin / interruptions
- The abrasive skin and any interruptions chip a fragile edge. Use a tougher K-grade with a honed edge and ease into the first cut.
- Frittering at the cut exit
- The unsupported corner breaks out as the tool exits. Reduce feed at exit or use a tougher grade.
- Abrasive dust
- Grey iron runs dry and the swarf is abrasive on the machine too — manage the dust.
Reference data
Frequently asked questions
What insert grade should I use for grey cast iron?
A CVD alumina-coated carbide in the ISO K class, K10–K20; ceramic for high-speed finishing. Match the ISO K class across brands and confirm the exact grade in the advisor.
Can I machine grey cast iron dry?
Yes — grey iron is normally run dry. It makes short chips and no built-up edge; the main thing to manage is the abrasive dust.
What cutting speed for grey cast iron with carbide?
Roughly Vc 150–350 m/min and fn 0.10–0.50 mm/rev, dry. Treat this as a starting band and confirm on a sample part.
Why does my edge chip on cast-iron skin?
The abrasive cast skin and interruptions chip a fragile edge; use a tougher K-grade with a honed edge and ease into the first cut.
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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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