Understanding Cobalt Content in Tungsten Carbide Grades

Introduction

Cobalt is the most common binder metal in cemented carbide. Its percentage directly determines the balance between hardness and toughness in every carbide grade.

Low Cobalt Grades

Low cobalt carbide offers the highest hardness and wear resistance. Grades like YG6 excel in finishing tools, fine stamping, and wire drawing where edge retention is critical. However, they are more brittle.

Medium Cobalt Grades

Medium cobalt grades balance hardness with toughness. YG8, YG11, and YG15 are general-purpose choices for stamping, drawing, and forming applications. They are the most versatile grades.

High Cobalt Grades

High cobalt carbide offers maximum impact resistance and transverse rupture strength. YG20 is used for cold heading, hot forging, and heavy stamping where shock loading is expected.

Cobalt and Corrosion

Higher cobalt content can make carbide more susceptible to corrosion in certain environments. Nickel-bonded carbide is available for corrosive applications despite high binder content.

Selecting the Right Cobalt Level

Match cobalt content to the application. When in doubt, start with a medium grade and adjust based on performance feedback. Consulting with a carbide supplier prevents costly grade mismatches.

Conclusion

Cobalt content is the primary lever for carbide grade selection. Understanding its effect on properties enables engineers to choose the optimal material for each tooling application.

References

GB/T 7714: GUPTA R, SONG J. Powder metallurgy processing and mechanical properties of cemented tungsten carbide composites[J]. International Journal of Refractory Metals and Hard Materials, 2020, 91: 105246.

APA 7th: Gupta, R., & Song, J. (2020). Powder metallurgy processing and mechanical properties of cemented tungsten carbide composites.

MLA 9th: Gupta, R., and J. Song. "Powder Metallurgy Processing and Mechanical Properties of Cemented Tungsten Carbide Composites."