Cobalt-Based
High-Performance Alloys
Engineered materials delivering exceptional wear resistance, corrosion protection, and thermal stability for the most demanding industrial applications.
Material Performance
Cobalt-based alloys offer superior performance characteristics across multiple critical parameters, making them ideal for extreme operating conditions.
Exceptional Wear Resistance
Superior resistance to abrasive, adhesive, and erosive wear mechanisms. Maintains surface integrity under high-stress sliding contact.
- Hardness up to 60 HRC
- Low friction coefficient
High-Temperature Stability
Retains mechanical properties and hardness at elevated temperatures. Excellent resistance to thermal fatigue and oxidation.
- Service temperature up to 1000°C
- Minimal thermal expansion
Corrosion Resistance
Outstanding resistance to chemical attack, oxidation, and sulfidation in aggressive environments.
- Acid and alkaline resistance
- Seawater and brine compatible
Erosion Protection
Superior resistance to particle impact erosion and cavitation damage in high-velocity fluid systems.
- Slurry and particle resistance
- Cavitation damage prevention
Galling Resistance
Excellent resistance to metal-to-metal adhesion and seizure under high-pressure contact conditions.
- Self-lubricating properties
- Prevents cold welding
Dimensional Stability
Maintains precise tolerances under thermal cycling and mechanical stress. Minimal distortion during service.
- Low thermal expansion coefficient
- Excellent creep resistance
Material Grade Specifications
Comprehensive comparison of cobalt-based alloy grades with chemical composition and mechanical properties.
| Grade | Co (wt%) | Cr (wt%) | W (wt%) | C (wt%) | Others (wt%) | Hardness (HRC) |
|---|---|---|---|---|---|---|
| ST1 | Bal. | 31.0 | 12.5 | 2.5 | Mn,Si,Ni,Mo,Fe | 51-55 |
| ST3 | Bal. | 31.0 | 12.5 | 2.3 | Mn,Si,Ni,Mo,Fe | 51-55 |
| ST4 | Bal. | 30.0 | 14.0 | 1.1 | Mn,Si,Ni,Mo,Fe | 40-46 |
| ST6 | Bal. | 29.0 | 4.5 | 1.2 | Mn,Si,Ni,Mo,Fe | 38-44 |
| ST6B | Bal. | 30.0 | 4.5 | 1.2 | Mn,Si,Ni,Mo,Fe | 33-43 |
| ST6K | Bal. | 29.0 | 4.5 | 1.7 | Mn,Si,Ni,Mo,Fe | 43-47 |
| ST12 | Bal. | 30.0 | 8.3 | 1.4 | Mn,Si,Ni,Mo,Fe | 44-49 |
| ST19 | Bal. | 31.0 | 10.5 | 1.8 | Mn,Si,Ni,Mo,Fe | 46-51 |
| ST20 | Bal. | 32.0 | 16.5 | 2.6 | Si,Ni,Mo,Fe | 56-60 |
| ST21 | Bal. | 27.0 | - | 0.3 | Mn (1.5%),Si,Ni,Mo (5.5%),Fe | 27-40 |
| ST25 | Bal. | 20.0 | 15.0 | 0.1 | Mn,Si,Ni (10.0%),Mo,Fe | 20-45 |
| ST31 | Bal. | 25.5 | 7.5 | 0.5 | Mn,Si,Ni (10.5%),Mo,Fe | 30-35 |
| ST694 | Bal. | 28.0 | 19.0 | 1.0 | Mn,Si (1.0%),Ni (5.0%),Mo,Fe,V (1.0%) | 47-51 |
| Grade | Co (wt%) | Cr (wt%) | Mo (wt%) | C (wt%) | Si (wt%) | Others (wt%) | Hardness (HRC) |
|---|---|---|---|---|---|---|---|
| T400 | Bal. | 8.5 | 28.5 | ≤ 0.1 | 2.6 | Ni,Fe | 48-58 |
| T800 | Bal. | 17.50 | 28.5 | ≤ 0.1 | 3.4 | Ni,Fe | 54-62 |
| ASTM-F75 | Bal. | 28.5 | 6.0 | < 0.35 | - | Mn,Fe | 26-30 |
Application Guide
- • ST 1, ST12: Extreme wear applications
- • ST 6: General purpose wear/corrosion
- • ST 21: Metal-to-metal sliding
- • ST 20: High-temperature fretting
Standards Compliance
- • UNS (Unified Numbering System)
- • ASTM specifications
- • AWS welding standards
- • GB Chinese national standards
Custom Formulations
We can develop custom alloy compositions to meet specific application requirements.
Request Technical ConsultationCobalt Alloys vs Carbide Alloys
Understanding the performance trade-offs between cobalt-based and tungsten carbide materials for critical component selection.
Cobalt-Based Alloys
Versatile performance for complex applications
Key Advantages
- ✓ Superior toughness: Excellent impact and shock resistance, ideal for dynamic loading conditions
- ✓ Thermal stability: Retains hardness at temperatures up to 1000°C without degradation
- ✓ Corrosion resistance: Outstanding performance in acidic, alkaline, and oxidizing environments
- ✓ Machinability: Can be machined, welded, and repaired more easily than carbides
- ✓ Galling resistance: Excellent for metal-to-metal contact and sliding applications
- ✓ Complex geometries: Suitable for intricate component designs and thin sections
Typical Applications
- Valve seats and trim for high-pressure systems
- Pump components in corrosive environments
- Extrusion tooling and dies
- Oilfield drilling and completion tools
Tungsten Carbide Alloys
Maximum hardness for abrasive conditions
Key Advantages
- ✓ Extreme hardness: Hardness values up to 70-75 HRC for maximum abrasion resistance
- ✓ Abrasion resistance: Superior performance against hard particle erosion
- ✓ Compressive strength: Excellent under high compressive loads
Limitations
- ✗ Brittleness: Prone to chipping and cracking under impact or thermal shock
- ✗ Corrosion sensitivity: Limited resistance to chemical attack compared to cobalt alloys
- ✗ Processing difficulty: Requires grinding; cannot be welded or easily repaired
- ✗ Design constraints: Limited to simple geometries; thick sections required
Best Suited For
- Cutting tools and wear plates
- Mining and drilling bits
- Pure abrasion applications without impact
Selection Decision Matrix
| Performance Factor | Cobalt Alloys | Carbide Alloys |
|---|---|---|
| Abrasive Wear Resistance | ⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ |
| Impact/Shock Resistance | ⭐⭐⭐⭐⭐ | ⭐⭐ |
| Corrosion Resistance | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ |
| High Temperature Performance | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ |
| Thermal Shock Resistance | ⭐⭐⭐⭐ | ⭐⭐ |
| Machinability | ⭐⭐⭐⭐ | ⭐⭐ |
| Weldability/Repairability | ⭐⭐⭐⭐⭐ | ⭐ |
| Complex Geometry Capability | ⭐⭐⭐⭐⭐ | ⭐⭐ |
Material Selection Recommendation
Choose Cobalt Alloys when: Applications involve impact loading, thermal cycling, corrosive environments, complex component geometry, or need for field repair. Ideal for valve systems, pump components, and high-temperature tooling.
Choose Carbide Alloys when: Maximum abrasion resistance is the primary requirement with minimal impact, corrosion, or thermal shock. Best for cutting tools, wear plates, and simple geometry applications.
Need Material Selection Guidance?
Our materials engineers can help you select the optimal cobalt alloy grade for your specific application requirements.