ISO P/M/K/N/S/H Carbide Grade Parameters Explained: Kyocera, TaeguTec, and Mitsubishi Complete Reference Guide

Introduction to ISO Carbide Grade Classification

Selecting the correct carbide grade is one of the most critical decisions in machining. The ISO (International Organization for Standardization) classification system provides a universal framework for categorizing cemented carbide cutting tools based on the workpiece material they are designed to machine. Understanding the six main ISO application classes—P, M, K, N, S, and H—is essential for optimizing tool life, surface finish, and productivity.

In this comprehensive reference guide, we compare carbide grade offerings from three leading manufacturers: Kyocera, TaeguTec, and Mitsubishi Materials. Each brand approaches grade development with unique substrate formulations, coating architectures, and sintering technologies. This guide provides side-by-side parameter data, recommended cutting speeds (Vc), feed rates (fz), and depth-of-cut ranges to help engineers make informed grade selections.

Understanding the ISO Grade Coding System

Each ISO class represents a primary workpiece material group, and numerical suffixes (05, 10, 15, 20, 25, 30, 40) indicate the grade’s position on the hardness-toughness spectrum. Lower numbers (e.g., P05) signify higher wear resistance and hardness, suitable for high-speed finishing. Higher numbers (e.g., P40) indicate greater toughness and deformation resistance, designed for roughing and interrupted cuts.

• ISO P – Steel, carbon steel, alloy steel, ferritic/martensitic stainless steel (machinable with continuous chip)
• ISO M – Stainless steel (austenitic, duplex), manganese steel, cast steel, other ductile materials with built-up edge tendency
• ISO K – Cast iron (gray, ductile, malleable), chilled cast iron, short-chip materials
• ISO N – Non-ferrous metals (aluminum, copper, brass, bronze, magnesium, zinc alloys)
• ISO S – Superalloys and titanium (Inconel, Hastelloy, Waspaloy, Ti-6Al-4V, other heat-resistant alloys)
• ISO H – Hardened materials (hardened steel >45 HRC, chilled cast iron, sintered metals, ceramics)

ISO P-Class: Steel Machining Grades

Steel machining represents the largest segment of carbide tool consumption. P-class grades must balance crater wear resistance (from high cutting temperatures), flank wear resistance, and toughness against variable chip loads. Modern P-class grades typically feature CVD-coated TiCN/Al2O3/TiN architectures on WC-Co substrates with cobalt contents ranging from 5% to 12%.

Grade Comparison Table — ISO P-Class

Recommended Cutting Parameters for ISO P-Class

Brand Notes: Kyocera’s CA6525 features a nano-textured Al2O3 layer that provides exceptional crater resistance at elevated speeds above 300 m/min. TaeguTec’s TT9025 utilizes their proprietary “Hard Nano Coating” (HNC) technology with a fine-grained TiCN base layer, offering a good balance between speed capability and toughness. Mitsubishi’s UP20M employs a thick CVD Al2O3 topcoat optimized for continuous cuts in alloy steel.

ISO M-Class: Stainless Steel Machining Grades

Stainless steel machining presents unique challenges: high work hardening rates, built-up edge (BUE) formation, poor thermal conductivity, and gummy chip formation. M-class grades typically employ PVD TiAlN or TiCN/TiAlN coatings on tougher substrates with higher cobalt content and finer grain structures to resist notch wear and thermal cracking.

Grade Comparison Table — ISO M-Class

Recommended Cutting Parameters for ISO M-Class

Brand Notes: Kyocera’s PR1225 uses a super-fine grain substrate with a low-friction PVD AlTiN coating, specifically engineered to minimize BUE in austenitic stainless steels. TaeguTec’s TT8020 features their “Super ZX” coating—a multi-layered PVD architecture with alternating TiAlN and TiSiN nanolayers that suppresses thermal cracking. Mitsubishi’s VP15TF is a workhorse M20–M30 grade with exceptional versatility across both continuous and lightly interrupted cuts.

ISO K-Class: Cast Iron Machining Grades

Cast iron machining is characterized by abrasive carbide particles in the workpiece microstructure, short discontinuous chips, and significant mechanical shock at the cutting edge. K-class grades prioritize abrasion resistance and edge strength. Gray cast iron (GCI) typically runs at higher speeds with CVD-coated grades, while ductile cast iron (DCI) requires tougher substrates due to its more ductile chip formation.

Grade Comparison Table — ISO K-Class

Recommended Cutting Parameters for ISO K-Class

Brand Notes: Kyocera’s CA6535 incorporates a high-density Al2O3 CVD coating optimized for the high cutting temperatures encountered in high-speed gray cast iron machining (up to 500 m/min). TaeguTec’s TT8115 provides excellent edge integrity in mixed production environments running both gray and ductile irons. Mitsubishi’s HTi10 features a thick single-phase α-Al2O3 coating that delivers superior thermal barrier properties at extreme cutting speeds.

ISO N-Class: Non-Ferrous Metal Machining Grades

Non-ferrous machining—primarily aluminum, copper, and brass—requires grades with excellent resistance to built-up edge and high hot hardness. For aluminum alloys, uncoated or diamond-coated (PCD) carbide grades are most common. The challenge lies in maintaining sharp cutting edges while resisting the abrasive wear from silicon particles in high-silicon aluminum alloys.

Grade Comparison Table — ISO N-Class

Recommended Cutting Parameters for ISO N-Class

Brand Notes: Kyocera’s TN610 ultra-fine grain grade delivers exceptional edge sharpness critical for achieving mirror surface finishes in aluminum turning. TaeguTec’s TT0830 PCD grade uses fine diamond grain size (2–5 μm) for superior wear resistance in hypereutectic aluminum-silicon alloys. Mitsubishi’s NP10 is a versatile general-purpose grade with optional DLC coating for reduced friction and improved chip flow in copper alloys.

ISO S-Class: Superalloy and Titanium Machining Grades

Machining heat-resistant superalloys (HRSA) and titanium alloys represents the most demanding application for carbide tools. These materials retain strength at high temperatures, exhibit low thermal conductivity (concentrating heat at the cutting edge), and cause severe notch wear and cratering. S-class grades rely on advanced PVD coatings, fine-grain substrates, and carefully engineered edge preparations.

Grade Comparison Table — ISO S-Class

Recommended Cutting Parameters for ISO S-Class

Brand Notes: Kyocera’s ST60M uses a high-aluminum-content AlTiN PVD coating with excellent hot hardness for finishing operations in nickel-based superalloys at the upper end of the speed range. TaeguTec’s TT8020, with its Super ZX nanolayer coating, resists thermal fatigue cracking in interrupted cuts typical of aerospace forgings. Mitsubishi’s VS1500 combines a tough fine-grain substrate with a nano-structured TiAlN/TiSiN multilayer coating for balanced performance in titanium and superalloy roughing.

ISO H-Class: Hardened Material Machining Grades

Hard turning—machining hardened steel components (45–65 HRC) to final finish with cubic boron nitride (CBN) or fine-grain carbide inserts—has become a viable alternative to grinding in many applications. H-class grades include both CBN for the hardest materials and high-hardness carbide grades for materials at the lower end of the hardness range (45–55 HRC).

Grade Comparison Table — ISO H-Class

Recommended Cutting Parameters for ISO H-Class

Brand Notes: Kyocera’s KBN700 is a high-CBN content grade with a TiN binder system optimized for continuous finishing cuts in case-hardened and through-hardened steels above 60 HRC. TaeguTec’s TT7200 medium-CBN grade offers good balance between wear resistance and chipping resistance, making it suitable for interrupted hard turning of gears and splined shafts. Mitsubishi’s MB730 leverages a unique CBN grain orientation technology that provides longer tool life in precision hard turning applications where dimensional accuracy is critical.

Coating Technology Comparison

Modern carbide tool performance is heavily dependent on coating technology. The three manufacturers employ different coating architectures and deposition technologies that contribute to distinct performance characteristics.

Chemical Vapor Deposition (CVD)

CVD coatings are thicker (typically 8–22 μm) and provide excellent wear resistance and thermal barrier properties. All three manufacturers offer CVD-coated grades primarily for steel and cast iron machining. Kyocera uses a proprietary “Micro-Alumina” layer structure in their CA65xx series, while TaeguTec’s TT90xx series features their “Alpha-Alumina” technology with controlled grain orientation. Mitsubishi’s CVD grades employ a “Columnar TiCN” underlayer for improved adhesion and wear resistance.

Physical Vapor Deposition (PVD)

PVD coatings are thinner (2–7 μm) and can be applied at lower temperatures, preserving substrate toughness. Kyocera’s PR-series uses “Megacoat” technology—a thick, smooth AlTiN PVD coating with excellent oxidation resistance. TaeguTec’s “Super ZX” coating features alternating nanolayers of TiAlN and TiSiN, creating a laminate structure that resists crack propagation. Mitsubishi’s VP-series employs a “Super Fire” coating with a nano-multi-layer architecture that enhances both wear resistance and surface smoothness.

Grade Selection Decision Framework

When selecting a carbide grade, follow this systematic approach:

1. Identify the workpiece material group – Determine which ISO class (P/M/K/N/S/H) applies based on workpiece material and hardness.
2. Define the operation type – Finishing, general-purpose, or roughing determines where on the numerical spectrum (05 vs. 40) you should select.
3. Assess cutting conditions – Continuous vs. interrupted cut, stability of the setup, available machine power, and coolant type all influence grade selection.
4. Start with the middle of the range – For new applications, begin with a mid-range grade (P20, M20, K20) and adjust toward harder (lower number) or tougher (higher number) grades based on observed wear patterns.
5. Match the failure mode to the grade – If experiencing crater wear or plastic deformation, move to a harder grade (lower number). If experiencing chipping or fracture, move to a tougher grade (higher number).

Conclusion

The ISO P/M/K/N/S/H carbide grade classification system provides a common language for comparing cutting tool grades across manufacturers. While Kyocera, TaeguTec, and Mitsubishi each bring unique technological approaches to substrate development and coating architecture, their grade ranges map reasonably well across the ISO spectrum.

For steel turning, Kyocera CA6525, TaeguTec TT9080, and Mitsubishi MC5015 are comparable high-performance P10 grades. In stainless steel, the Kyocera PR1535, TaeguTec TT8020, and Mitsubishi VP15TF occupy similar M20–M30 territory. For cast iron, the K10–K20 grades—Kyocera CA5515, TaeguTec TT8115, and Mitsubishi UC5115—are direct competitors. In superalloys and hardened materials, the performance differences become more pronounced, and application testing is strongly recommended.

Use the parameter tables in this guide as starting points, and always validate with on-machine trials under your specific production conditions. Tool life, surface finish, and productivity targets should drive the final grade selection, not brand preference alone.