Tungsten carbide is one of the hardest engineering materials used in modern industry, ranking close to diamond on the Mohs hardness scale. Its outstanding resistance to scratching and abrasion makes it a preferred choice for wear parts, cutting tools, and heavy-duty components where long service life, dimensional stability, and reliable performance under extreme conditions are essential.
What Is the Mohs Hardness of Tungsten Carbide?
Tungsten carbide typically measures between 8.5 and 9.5 on the Mohs hardness scale, placing it just below diamond and above most natural and engineered materials. This means it can resist scratching from quartz, topaz, and most ceramics, making it exceptionally suitable for severe abrasion environments. Rettek produces tungsten carbide parts with controlled grain size and binder composition to achieve stable, high hardness for industrial applications.
The Mohs scale is a relative scratch-resistance ranking, not an absolute strength test. A higher value indicates that the material can scratch those with lower values. In practical terms, a 9-level material such as high-grade tungsten carbide maintains surface integrity far longer than steel, cast iron, or hardened alloys when exposed to sand, rock, or mineral particles.
| Material | Typical Mohs Hardness | Relative Wear Resistance |
|---|---|---|
| Steel | 4 – 6.5 | Moderate |
| Quartz | 7 | High |
| Corundum (Al₂O₃) | 9 | Very high |
| Tungsten Carbide | 8.5 – 9.5 | Extremely high |
| Diamond | 10 | Maximum |
Why Does Tungsten Carbide Have Such High Hardness?
The exceptional hardness of tungsten carbide comes from its strong atomic bonding between tungsten and carbon, forming a dense crystal structure. This structure resists plastic deformation and surface penetration. The addition of a metallic binder, usually cobalt, provides toughness while retaining high hardness. Through precise control of powder purity, grain size, and sintering temperature, Rettek ensures an optimal balance between extreme wear resistance and mechanical reliability.
How Does Tungsten Carbide Compare With Other Industrial Materials?
Compared with steel, bronze, or tool alloys, tungsten carbide offers several times higher scratch and abrasion resistance. While advanced ceramics may reach similar hardness, they are often more brittle. Tungsten carbide combines near-ceramic hardness with much higher fracture toughness, making it suitable for impact-prone wear parts such as crusher tips, snow plow blades, and HPGR studs manufactured by Rettek.
What Factors Influence the Mohs Hardness of Tungsten Carbide?
Mohs hardness is affected mainly by grain size, cobalt content, and sintering quality. Finer grains and lower cobalt content generally increase hardness, while higher cobalt improves toughness but slightly reduces scratch resistance. Vacuum sintering and high-purity raw materials further enhance density and uniformity. Rettek adjusts these parameters according to the working conditions of each application.
How Is the Hardness of Tungsten Carbide Verified?
In industry, hardness is confirmed through laboratory methods such as Vickers or Rockwell testing, which correlate well with Mohs values. Scratch tests using reference minerals provide qualitative confirmation. Rettek conducts systematic hardness and microstructure inspections to ensure every batch meets the specified performance level for wear resistance and service life.
Why Is Mohs Hardness Important for Wear Parts?
Higher Mohs hardness directly translates into improved resistance to scratching, grooving, and surface fatigue. For components operating in abrasive media such as sand, ore, ice, or slurry, this means slower wear rates, longer replacement intervals, and lower operating costs. Rettek designs its carbide components to maintain high hardness throughout the service life, even under heavy load and thermal cycling.
Rettek Expert Views
“Mohs hardness is a clear indicator of how well a material will resist abrasion in real operating conditions. At Rettek, we focus on producing tungsten carbide with stable, high scratch resistance through strict control of grain size, cobalt distribution, and sintering density. This allows our wear parts to maintain dimensional accuracy and surface integrity in crushers, mining equipment, and snow removal systems, delivering consistent performance and extended service life for customers worldwide.”
Can Rettek Supply High-Hardness Tungsten Carbide for OEM Applications?
Rettek offers a full range of high-hardness tungsten carbide grades for OEM and industrial users. With complete in-house production, from powder preparation to final grinding and brazing, Rettek can customize hardness, toughness, and geometry to match specific operating loads, impact levels, and abrasion intensity.
How Does High Hardness Improve Equipment Efficiency?
Components with higher Mohs hardness maintain smooth surfaces and tight clearances for longer periods. This reduces friction losses, vibration, and unexpected shutdowns. In crushing, conveying, and snow-clearing systems, Rettek’s high-hardness carbide parts help stabilize performance, extend maintenance intervals, and lower total lifecycle costs.
Conclusion
Tungsten carbide, with a Mohs hardness of approximately 8.5 to 9.5, stands among the hardest and most wear-resistant materials available for industrial use. Its ability to withstand severe abrasion, maintain shape under load, and resist surface damage makes it indispensable for demanding applications. By selecting the appropriate grade, ensuring precise manufacturing, and applying correct maintenance practices, users can fully benefit from this exceptional material. With advanced production technology and strict quality control, Rettek provides high-hardness tungsten carbide solutions that deliver long service life, reliable performance, and measurable cost savings across a wide range of industries.
FAQs
What is the typical Mohs hardness range of tungsten carbide?
It usually falls between 8.5 and 9.5, depending on grade composition and grain size.
Is tungsten carbide harder than most ceramics?
It is comparable in hardness to advanced ceramics but offers much higher toughness and impact resistance.
Does higher cobalt content reduce Mohs hardness?
Yes, increasing cobalt improves toughness but slightly lowers scratch resistance, so grades are selected based on operating conditions.
How does tungsten carbide compare with diamond on the Mohs scale?
Diamond is rated 10, while tungsten carbide is slightly lower, but still far harder than most engineering materials.
Can Rettek customize hardness for specific applications?
Yes, Rettek can tailor carbide grades and microstructure to achieve the optimal balance of hardness and toughness for each OEM or industrial requirement.