ISO K — Cast Iron · K10
K10 — Grey cast iron (hard)
Hardness range: 200–280 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 — K10
- ISO designation
- K10 (ISO K — Cast Iron)
- Material
- Grey cast iron (hard)
- Hardness
- 200–280 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 hard / pearlitic grey iron — starting point
- ISO application class
- K (cast iron). Harder pearlitic grey iron (200–280 HB) is more abrasive than soft grey iron, so favour a more wear-resistant grade and a lower speed. Match the ISO K class across brands rather than the brand name (Sandvik, Kennametal, Iscar, Walter, Seco and Mitsubishi each publish one), then confirm the exact grade for your condition.
- Grade & coating
- CVD alumina (Al₂O₃)-coated carbide, K10–K15 for wear resistance; ceramic / SiAlON for high-speed finishing.
- Geometry
- Negative geometry, honed edge for cast skin and interruptions. Short chips and no built-up edge.
- Starting parameters
- Vc ≈ 120–300 m/min, fn ≈ 0.10–0.40 mm/rev, dry. Lower than soft grey iron because of the harder matrix — confirm in the advisor or on a sample part.
Selection table: hard / pearlitic grey iron
| Operation | Geometry | ISO class | Coating family | Coolant | First check |
|---|---|---|---|---|---|
| Roughing | Negative geometry, honed edge for cast skin | K10–K15 | CVD alumina (Al₂O₃)-coated carbide | Dry | Heavier abrasive flank wear than soft grey iron: lower the speed |
| Finishing | Negative geometry; short chips, no built-up edge | K10–K15 | CVD alumina carbide; ceramic / SiAlON for high-speed finishing | Dry | Wear-resistant grade for the harder matrix |
| Interrupted cut | Honed edge for skin and interruptions | K10–K15 (tougher end) | CVD alumina carbide | Dry | Chipping on cast skin: tougher grade, ease in |
| Low rigidity / thin wall | Negative geometry with honed edge; support the part | K10–K15 | CVD alumina carbide | Dry | Frittering at exit: reduce feed at exit |
hard / pearlitic grey iron: what goes wrong, and what to check first
- Abrasive flank wear
- Heavier than on soft grey iron. Use a wear-resistant CVD-alumina K-grade and keep the speed sensible.
- Edge chipping on cast skin
- The abrasive skin and interruptions chip a fragile edge. Use a tougher grade with a honed edge and ease in.
- Frittering at the cut exit
- The unsupported corner breaks out on exit. Reduce feed at exit or use a tougher grade.
- Abrasive dust
- Runs dry; the dust is abrasive on the machine too, so manage it.
Reference data
Frequently asked questions
What insert grade for hard pearlitic grey iron?
A wear-resistant CVD alumina-coated carbide, K10–K15, or ceramic for high-speed finishing. Match the ISO K class across brands and confirm the grade in the advisor.
Why does hard grey iron wear tools faster than soft?
The harder pearlitic matrix is more abrasive, so flank wear climbs; drop the speed and use a more wear-resistant grade.
What cutting speed for hard grey iron?
Roughly Vc 120–300 m/min, fn 0.10–0.40 mm/rev, dry — lower than soft grey iron. Confirm on a sample part.
Can I run hard grey iron dry?
Yes; grey iron makes short chips and no built-up edge. Manage the abrasive dust.
Are you overpaying on your Grey cast iron (hard) inserts? Paste your insert list and get a cost audit in about 30 seconds: cross-brand equivalents at the same ISO application position, and where you are likely overpaying. No signup, no sales call.
Related materials