Common YG Grades of Cemented Carbide Bars

When selecting the right grades of Cemented Carbide Bars, it’s essential to understand that YG grades are typically used to categorize tungsten carbide grades that contain cobalt as the binder material. The “YG” designation refers to Y being for carbide material and G indicating cobalt as the binder. The numerical value after “YG” generally represents the cobalt content in the material.

Tungsten carbide grades in the YG series are designed to provide a balance of hardness and toughness, with the cobalt content affecting the toughness and the carbide content impacting the hardness and wear resistance.

Let’s explore how to choose the right YG tungsten carbide grade for your specific application, based on its key properties and typical uses:

1. Understand the YG Series Designation

The YG grades are differentiated based on their cobalt content and, to a lesser degree, the grain size of the carbide. Common YG grades include:

• YG6: 6% cobalt content
• YG8: 8% cobalt content
• YG10: 10% cobalt content
• YG15: 15% cobalt content
• YG20: 20% cobalt content

Generally:

• Higher cobalt content increases toughness and impact resistance, but reduces wear resistance.
• Lower cobalt content increases hardness and wear resistance, but reduces toughness.

2. Key Properties to Consider When Choosing YG Grades

1. Hardness vs. Toughness

• Hardness: Higher tungsten carbide content (and lower cobalt content) provides better wear resistance, which is critical for cutting tools, wear-resistant parts, and abrasion-heavy applications.
• Toughness: Higher cobalt content enhances the toughness, making the material more resistant to cracking and chipping under impact or vibration.

2. Wear Resistance vs. Impact Resistance

• Wear Resistance: Tungsten carbide with a higher carbide content (less cobalt) is more wear-resistant. These grades are typically used for cutting tools and components exposed to abrasive environments.
• Impact Resistance: Tungsten carbide with higher cobalt content is more impact-resistant. These grades are more suitable for heavy-duty applications like mining tools or heavy machinery.

3. Grain Size

• Fine Grain Size: Fine-grain carbide has better hardness and wear resistance but lower toughness. It's used in applications like high-precision cutting tools.
• Coarse Grain Size: Coarse-grain carbide offers higher toughness but lower hardness. It's used in applications that require resistance to impact and fatigue, such as mining tools.

3. Choosing the Right YG Grade Based on Application

1. Cutting Tools (Milling, Drilling, Turning, etc.)

• Recommended Grade: YG6 to YG8 (Low cobalt content, higher tungsten carbide content)
• Properties Needed: Hardness, wear resistance, and precision.
• Use Case: For high-speed machining of materials like steel, stainless steel, and non-ferrous materials. These grades are excellent for applications where wear resistance is essential, and toughness requirements are moderate.
• Example: YG6 (fine grain) would be used for cutting tools requiring high hardness and wear resistance.

2. Heavy Wear Applications (Mining, Earthmoving, etc.)

• Recommended Grade: YG10 to YG15 (Moderate to high cobalt content, with a good balance of toughness and wear resistance)
• Properties Needed: Impact resistance, toughness, and abrasion resistance.
• Use Case: For mining tools, drill bits, and rock crushers, where the material is exposed to high levels of impact and abrasion.
• Example: YG15 (coarser grain and higher cobalt content) would be used in mining and construction tools to withstand heavy impact and abrasive conditions.

3. High-Impact, Fatigue-Prone Applications

• Recommended Grade: YG15 to YG20 (Higher cobalt content for better toughness)
• Properties Needed: Toughness, resistance to cracking, and vibration resistance.
• Use Case: For tools exposed to heavy impact or vibration (e.g., hammering tools, grinding media).
• Example: YG20 (coarse grain, high cobalt content) is ideal for heavy-duty applications like rock drills, impact hammers, or machinery exposed to vibration.

4. Precision Molds, Dies, and Tools

• Recommended Grade: YG6 to YG8 (Fine-grain, low cobalt content)
• Properties Needed: High hardness, sharp edges, and wear resistance.
• Use Case: For precision molding, stamping, and cutting tools that require sharpness and excellent wear resistance in high-precision machining of softer metals and plastics.
• Example: YG6 would be optimal for fine-grain cutting tools that need to maintain sharp edges for precise work.

5. Forming Tools and Dies (Stamping, Forging, etc.)

• Recommended Grade: YG8 to YG10 (Balanced hardness and toughness)
• Properties Needed: Good toughness to resist chipping and wear resistance for longevity.
• Use Case: For forging dies, extrusion dies, and forming tools that experience both high wear and impact.
• Example: YG10 would work well for dies used in forming and extrusion processes that require a balance of impact resistance and wear resistance.

4. Summary Table for YG Grades

5. Factors to Consider When Choosing the Right YG Grade

• Application Type: Will the tool be exposed to high impact, high wear, or precision cutting? If impact resistance is more critical, a grade with higher cobalt content (YG10, YG15, YG20) should be chosen. For wear resistance, a lower cobalt grade (YG6, YG8) is ideal.
• Material to be Machined: Consider the hardness of the material being machined. Softer materials require tools with higher wear resistance, while harder materials demand toughness to prevent chipping.
• Work Environment: Applications exposed to extreme temperatures, vibrations, or harsh conditions might require higher cobalt content for added toughness (YG15, YG20).
• Tool Life Expectancy: For tools that need to last longer under heavy wear conditions, consider higher tungsten content (lower cobalt).

Conclusion

Choosing the right YG tungsten carbide grade depends on the specific requirements of your application, including factors like hardness, toughness, wear resistance, and impact resistance.

• YG6 and YG8 are ideal for precision cutting and general machining.
• YG10 and YG15 provide a balance of wear resistance and toughness for mining tools, cutting tools, and forming dies.
• YG20 is best suited for high-impact applications, offering the greatest toughness.

Understanding the trade-off between wear resistance and toughness will help you select the most suitable YG grade for your specific needs.