Tungsten Carbide (WC) grades are primarily classified by the percentage of cobalt (Co) binder, typically ranging from ~3% to 25%. Cobalt acts as a metallic binder that holds WC grains together and directly controls the balance between hardness, toughness, and wear resistance.
WC–Co is the most widely used cemented carbide (hardmetal) system:
• WC (hard phase) → extreme hardness & abrasion resistance
• Co (binder phase) → toughness, crack resistance & strength
The material is a two-phase composite consisting of WC grains (0.2–10 µm) uniformly embedded in a metallic cobalt matrix.
Classification by Cobalt Content
• Low Co – Ultra-hard, wear-resistant
• Medium Co – Balanced performance
• High Co – Tough, impact-resistant
Common WC–Co Grades & Composition
| Grade Category | WC (%) | Co (%) |
|---|---|---|
| Ultra-Hard | 94–97 | 3–6 |
| Hard / Wear-Resistant | 90–94 | 6–10 |
| General Purpose | 86–90 | 10–14 |
| Impact-Resistant | 80–86 | 14–20 |
| Shock-Resistant | 70–80 | 20–30 |
Strengthening & Metallurgical Behavior
Microstructure
• Angular WC grains uniformly distributed
• Cobalt wets WC grains during sintering
• Grain size + Co content define final properties
Strengthening Mechanisms
✔ Load bearing by WC grains
✔ Plastic deformation of Co binder
✔ Crack deflection & energy absorption
✔ Grain size refinement (sub-micron WC)
Failure Modes
• Low Co → brittle fracture
• High Co → plastic deformation & adhesive wear
Refining & Processing Properties
Manufacturing Process
• WC powder synthesis (carburization)
• Cobalt powder addition
• Ball milling (homogenization)
• Spray drying
• Pressing (uniaxial / CIP)
• Vacuum sintering (1350–1450 °C)
• Optional HIP treatment
• Grinding / EDM finishing
Machinability
⚠ Not machinable by conventional cutting
✔ Ground with diamond wheels
✔ EDM used for complex shapes
Available Forms
✔ ISO / ANSI inserts
✔ Rods (solid & coolant-hole)
✔ Plates & blanks
✔ Wear parts (bushes, nozzles)
✔ Mining & drilling tools
✔ Custom near-net-shape components
Key Characteristics by Co Content
Low Co (3–6%)
✔ Extreme hardness
✔ Outstanding abrasion resistance
❌ Brittle, low impact resistance
Medium Co (6–14%)
✔ Balanced hardness & toughness
✔ Most widely used grades
High Co (14–30%)
✔ Excellent shock & impact resistance
✔ Crack resistant
❌ Lower wear resistance
Typical Applications
3–6% Co
Wire drawing dies, cold forming dies, abrasive wear plates, seal rings
6–10% Co
Finishing cutting tools, PCB drills, end mills
10–14% Co
General machining inserts, mining buttons, wear sleeves
14–20% Co
Rock drilling tools, oil & gas wear parts, hot forging dies
20–30% Co
Impact tools, crusher components, heavy shock applications
Material Comparison
| Material | Hardness | Toughness | Wear Resistance |
|---|---|---|---|
| Pure Tungsten | Low | Low | Low |
| WNiFe | Medium | High | Medium |
| W–Cu | Medium | Medium | Low |
| WC–Co | Very High | Adjustable | Very High |
Why Choose WC Grades by Co Binder Content?
WC–Co grades allow precise control of hardness, toughness, and wear resistance by adjusting cobalt content. From ultra-hard 3% Co grades for abrasion to shock-resistant 25% Co grades, WC–Co remains the most versatile and dominant hardmetal system for cutting tools, mining, oil & gas, and wear-critical industries.