Six ISO application classes, eight brands, and one honest caveat: a grade code tells you less than you think. This is the map — and what to check before you trust it.
Send us the code — or just a photo of the insert box. We identify the ISO class, confirm the substrate and coating, name the Chinese plant that makes the equivalent, and return a quotation within 48 hours. The cross-reference itself costs you nothing.
Every insert maker invents its own grade codes. Almost nothing about them is regulated. The exception is ISO 513, which defines six application classes by workpiece material. That is the common language you can rely on:
| ISO class | Colour | Workpiece material | Typical composition | ISO sub-grades |
|---|---|---|---|---|
| P | Blue | Carbon & alloy steel | WC–TiC–TaC–Co | P01–P50 |
| M | Yellow | Stainless steel & cast steel | WC–TiC–TaC–Co | M01–M40 |
| K | Red | Cast iron, non-ferrous, non-metals | WC–Co | K01–K40 |
| N | Green | Aluminium, copper, non-ferrous alloys | WC–Co + additives | N01–N30 |
| S | Orange | Superalloys & titanium | WC–TiC–TaC–Co | S01–S30 |
| H | Grey | Hardened steel & chilled cast iron | WC–Co + additives | H01–H30 |
Within each class the number runs from wear-resistant (low number) to tough (high number): P01 is a hard finishing grade, P50 a tough roughing grade. This is the only part of grade selection that is internationally standardised — ISO 513.
This is the table most people are looking for when they search for a grade chart. It maps the common turning grades of the major brands onto the ISO application classes.
| ISO class | Sandvik Coromant | Kennametal | Iscar | Mitsubishi | Seco | Walter | Tungaloy |
|---|---|---|---|---|---|---|---|
| P10 finishing | GC4415, GC4315 | KCP10B, KCP10 | IC8150, IC9150 | MC6115, MC6015 | TP1501, TP1500 | WPP10G, WPP10S | T9215, T9115 |
| P20–P25 general | GC4425, GC4325 | KCP25C | IC8250 | MC6125, MC6025 | TP2501, TP2500 | WPP20G | T9225, T9125 |
| P30–P35 roughing | GC4235, GC4335 | KCP30B, KCP40B | IC8350, IC9350 | MC6135, MC6035 | TP3501, TP3500 | WPP30G, WPP30S | T9235, T9135 |
| P40 heavy roughing | GC4240, GC4340 | KCP40B | IC5400 | UH6400, US735 | TP4000 | WPP30G | T9235 |
| M / S stainless, Inconel, Ti | GC1525, GC2220 | KCU10, KCU25 | IC907, IC908 | VP15TF, UE6020 | CP500, TS2500 | WPP05S | AH120, T9125 |
| K cast iron (uncoated) | H13A, 1010 | K313, K68 | IC20, IC28 | HTi10, UT20T | CBN300, TS2500 | WPP30S | T9115, T9215 |
| H hardened steel | CB7015, CB7025 | KU10, KYS30 | IB50, IB55 | MB8025, BC8020 | CBN300 | WCB10 | DX140, SH725 |
Read this table as a starting point, not a guarantee. Grades listed in the same ISO class can still differ by cobalt content, grain size, edge preparation and coating thickness — and those differences decide whether a tool survives your operation. Compiled from publicly available manufacturer catalogues and published grade charts. We confirm the actual substrate by spectrometer before quoting, and we tell you where two grades are not interchangeable.
There is no formal standard, but most manufacturers follow the same three-part structure:
GC (and CT, CC, CB). Kennametal uses KC, KCU, KCP, K. Iscar uses IC. Mitsubishi uses MC, VP, UE, US. Tungaloy uses T, AH, DX.43 family — GC4305, GC4315, GC4325, GC4335 — is one thick CVD coating on four different substrates.Treat the third part as a strong hint rather than a rule — manufacturers do not always follow it, and they change it between product generations.
Two grades both labelled P25 can behave very differently, because the ISO class says nothing about the two things that actually set tool life: substrate composition and coating.
| ISO grade | WC content | Co binder | Grain size | Character |
|---|---|---|---|---|
| K10 | 94–96% | 4–6% | Ultrafine / fine | High hardness, excellent wear resistance, low toughness |
| K20 | 92–94% | 6–8% | Fine | Balanced wear resistance and toughness |
| K30 | 88–92% | 8–12% | Medium | Higher toughness, heavy load |
| M10 | 93–95% | 5–7% | Fine | Wear resistance for stainless finishing |
| M20 | 91–93% | 7–9% | Fine / medium | General-purpose machining |
| M30 | 88–91% | 9–12% | Medium | Toughness for interrupted cutting |
| P10 | 92–94% | 6–8% | Fine | High-speed steel finishing |
| P20 | 90–92% | 8–10% | Medium | General steel machining |
| P30 | 87–90% | 10–13% | Medium / coarse | High toughness, heavy cutting |
| P40 | 85–88% | 12–15% | Coarse | Maximum toughness, impact resistant |
Typical ranges. A grade sold as “K20” by two different plants can sit anywhere in the range — and cobalt content is the single largest driver of both price and tool life. This is why we run a spectrometer on the delivered batch rather than trusting the label.
| CVD (chemical vapour deposition) | PVD (physical vapour deposition) | |
|---|---|---|
| Thickness | 5–25 µm | 2–6 µm |
| Typical layers | MT-TiCN, Al2O3, TiN top coat | TiAlN, AlTiN, AlCrN, TiB2, DLC |
| Heat resistance | ~800 °C | ~900 °C |
| Edge condition | Thicker, more rounded edge | Sharper edge possible; can be ground then coated |
| Bond to substrate | Chemical bond, higher adhesion | Mechanical bond; residual compressive stress raises toughness |
| Best for | Roughing, steel and cast iron, high speed | Stainless, aluminium, titanium, finishing, interrupted cuts |
A coating specified at 3 µm of AlTiN frequently measures 1.5 µm on a delivered batch. We measure it by ball-crater (Calotest) and adhesion by Rockwell indentation before we accept a shipment.
Each brand page below covers that maker’s naming system, its common turning grades, and the ISO class each one targets.
Grade cross reference hub
Kennametal grades
Sandvik Coromant grades
Iscar grades
Mitsubishi grades
Tungaloy grades
Seco grades
Walter grades
CNMG inserts
Turning insert shapes
Milling inserts (APMT / APKT)
Request a sourcing proposal → · Interactive grade chart → · What tolerance actually costs →
the carbide tooling price indexhow a sourcing order actually runsend mill price build-up