Cemented Carbide Classification: YG, YT, and YW Grades

Cemented carbide is a powder metallurgy product made by sintering hard carbide particles with a metallic binder, most commonly cobalt. The resulting material is extremely hard, wear-resistant, and capable of maintaining a sharp cutting edge at high temperatures. These properties make cemented carbide the backbone of modern cutting tools, tungsten carbide burs, milling inserts, and wear parts across industries ranging from metalworking to dentistry.

But not all cemented carbide is the same. Different combinations of carbide compounds and binder metals produce materials with very different hardness, toughness, and thermal resistance characteristics. Understanding cemented carbide classification helps you select the right grade for each application and avoid premature tool failure.

In this article, we break down the three major cemented carbide categories used across machining and tooling industries. Each category has distinct strengths that make it better suited for certain workpiece materials and cutting conditions. By the end, you will know which grade family to reach for based on the metal you are cutting, the type of operation, and the rigidity of your machine setup.

How Cemented Carbide Is Classified

The international ISO classification system groups cemented carbides by application (P, M, and K groups), but in Chinese industry standards, where much of the world's carbide is produced, the classification follows the composition of the carbide phase. There are three primary categories:

1. YG — Tungsten cobalt carbide (WC + Co)
2. YT — Titanium cobalt carbide (WC + TiC + Co)
3. YW — General-purpose cemented carbide (WC + TiC + TaC/NbC + Co)

Each category has multiple grades with different ratios of carbide to binder metal, giving engineers and machinists a wide selection of performance profiles.

1. Tungsten Cobalt Carbide (YG Series)

The YG series is the simplest cemented carbide composition: tungsten carbide (WC) particles bound with cobalt (Co). The number after “YG” indicates the cobalt percentage. For example, YG6 contains 6% cobalt and 94% tungsten carbide, while YG8 contains 8% cobalt.

Common YG Grades

Key Properties

• Higher cobalt = better toughness. More cobalt means the material can absorb impact and vibration without chipping. YG8 handles rough, interrupted cuts well.
• Lower cobalt = better hardness and wear resistance. YG3 holds a sharper edge longer but is more brittle and unsuitable for heavy impact.
• Good thermal conductivity. Tungsten cobalt carbides transfer heat away from the cutting edge efficiently.

Typical Applications

YG grades are the standard choice for machining cast iron, non-ferrous metals (aluminum, copper, brass), and non-metallic materials. They also perform well when rough-machining hardened steel and stainless steel parts, where vibration resistance matters more than anti-crater-wear properties.

2. Titanium Cobalt Carbide (YT Series)

The YT series adds titanium carbide (TiC) to the tungsten carbide and cobalt mixture. The number after “YT” represents the titanium carbide percentage. YT5 contains 5% TiC, YT15 contains 15% TiC, and YT30 contains 30% TiC.

Common YT Grades

Key Properties

• Reduced friction coefficient. Titanium carbide forms a barrier that limits chemical bonding between the tool and the steel workpiece, reducing crater wear on the rake face.
• Higher hot hardness. TiC raises the temperature at which the tool maintains its hardness, allowing faster cutting speeds.
• Increased brittleness. The trade-off for hardness gains is lower bending strength and toughness. YT30 is particularly fragile and cannot tolerate interrupted cuts or vibration.

Typical Applications

YT grades are designed specifically for cutting steel. The higher the TiC content, the faster the cutting speed but the smoother the cut must be. YT5 handles roughing operations, YT15 is the workhorse for general steel machining, and YT30 is reserved for high-speed finishing passes on stable setups with minimal vibration.

3. General-Purpose Cemented Carbide (YW Series)

The YW series builds on the YG and YT formulations by adding small amounts of rare metal carbides, typically tantalum carbide (TaC) and niobium carbide (NbC). These additions refine the grain structure and improve several performance characteristics simultaneously.

Common YW Grades

Key Properties

• Improved hot hardness and oxidation resistance. The rare carbide additions keep the tool performing well at high temperatures where YG and YT grades would soften.
• Better wear resistance without excessive brittleness. Tantalum and niobium carbides refine the grain structure, producing a tougher material than comparable YT grades at similar hardness levels.
• True versatility. YW grades can machine steel, cast iron, non-ferrous metals, and exotic alloys, making them practical when a shop needs one tool to handle mixed work.

Typical Applications

YW grades are reserved for difficult-to-machine materials: high-strength steel, heat-resistant superalloys, stainless steel, and titanium alloys. Their broad capability also makes them useful in job shops that process a variety of metals and cannot justify stocking many specialized grades. The main drawback is cost, as YW grades are significantly more expensive than YG or YT equivalents.

Choosing the Right Cemented Carbide Grade

Selecting the correct grade requires matching the carbide properties to your specific machining conditions. Here is a practical decision framework:

1. Identify the workpiece material. Cast iron and non-ferrous metals point to YG grades. Carbon and alloy steels point to YT grades. Stainless steel, superalloys, and mixed-material jobs point to YW grades.
2. Determine the operation type. Roughing with interrupted cuts demands high toughness (higher cobalt, lower TiC). Finishing at high speed demands high hardness and hot hardness (lower cobalt, higher TiC).
3. Evaluate the setup rigidity. Flexible setups with vibration favor tougher grades like YG8 or YT5. Rigid setups on stable machines can exploit the hardness of YG3 or YT30.
4. Consider cost vs. tool life. YW grades last longer on difficult materials but cost more upfront. For standard steel and cast iron work, YG and YT grades offer better value.

When in doubt, start with a mid-range grade within the appropriate category. YG6 is a safe starting point for cast iron work, YT15 covers most steel machining situations, and YW1 is a reliable first choice for stainless steel and superalloys. From there, adjust the cobalt or TiC percentage based on whether you need more toughness or more wear resistance for your specific conditions.

For a deeper look at how tungsten carbide is used in dental rotary instruments, see our tungsten carbide bur guide. If you are comparing carbide tools with diamond alternatives, our article on diamond burs vs carbide burs covers the performance trade-offs in detail.

Summary Comparison of All Three Categories

Cemented carbide classification may seem technical, but the core logic is straightforward: cobalt controls toughness, titanium carbide controls hardness and anti-wear behavior on steel, and rare carbide additions provide all-around performance for the most demanding applications. Match the grade to the material and operation, and your cutting tools will perform at their best.