Choosing the right insert grade is the difference between 60 parts per edge and 6. This guide covers ISO P/M/K/N/S/H classifications and how to match grades to your material and operation.
| ISO Group | Color | Material | Example Grades |
|---|---|---|---|
| P | Blue | Steel, cast steel | P10 (finishing), P25 (general), P40 (roughing) |
| M | Yellow | Stainless steel | M20 (austenitic), M30 (general), M40 (roughing) |
| K | Red | Cast iron | K10 (finishing), K20 (general), K30 (roughing) |
| N | Green | Non-ferrous (Al, Cu, brass) | Sharp, polished, often uncoated |
| S | Brown | Superalloys, titanium | Tough substrate, AlTiN coating, low speeds |
| H | Grey | Hardened steel (45-65 HRC) | CBN or ceramic, hard turning |
Finishing (01-15): Hard, wear-resistant grades. Fine grain carbide, thin PVD coating. Maximum surface finish, light depths of cut.
General Purpose (20-30): Balanced toughness and wear resistance. The "first choice" grade for most shops. Covers 80% of applications.
Roughing (35-50): Tough grades with higher cobalt content. Resist impact and thermal shock. For heavy cuts, interrupted cuts, and unstable setups.
For a complete cross-reference between manufacturers, use our Carbide Grade Cross Reference Chart and Coating Selector Tool.
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