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Stellite is a cobalt-based premium alloy known for its exceptional wear, galling, and corrosion resistance, making it a popular choice for hard-facing critical valve components such as seats, discs, stems, and trims in high-wear and severe service applications.

Properties

Properties

  • Outstanding Wear & Galling Resistance – Maintains integrity in metal-to-metal contact applications, reducing friction and surface damage.
  • Excellent High-Temperature Strength – Retains hardness and mechanical properties up to 540°C to 870°C (1000°F to 1600°F) depending on grade.
  • Superior Erosion & Corrosion Resistance – Resists slurries, steam erosion, and corrosive fluids in tough service conditions.
  • Low Friction Coefficient – Reduces torque requirements and minimizes seizing in high-cycle valves.
  • Long Service Life – Extends valve performance in high-pressure, high-velocity flow environments.

Stellite vs. Other Valve Materials
• Superior to stainless steel in terms of galling and wear resistance
• More wear-resistant than Inconel® or Monel®, but less corrosion-resistant in certain highly acidic environments
• Preferred for hard-facing over HVOF coatings where impact resistance is critical

Common Stellite Grades Used in Valves
• Stellite 6 – Most common grade, offering a balance of wear, corrosion, and impact resistance
• Stellite 21 – Better for corrosive environments with moderate wear demands
• Stellite 12 – Higher hardness for more extreme abrasion conditions

Limitations

Limitations

  • Higher Cost – More expensive than standard stainless steels or hard chrome due to cobalt content.
  • Challenging to Machine – Requires specialized machining techniques and tools.
  • Heavier Coatings May Require Precision Grinding – To achieve tight tolerances post-hard-facing.

Common Applications

Common Applications

Control & Severe Service Valves – Ideal for high-pressure steam and throttling applications.
Power Generation Valves – Used in boiler feedwater, turbine, and superheated steam systems.
Oil & Gas Valves – Suitable for abrasive and corrosive service in wellheads, choke valves, and refinery applications.
Mining & Slurry Valves – Protects critical components in abrasive slurry and solids-handling processes.
Nuclear Valves – Applied in nuclear power plants for safety-related components due to wear resistance and longevity.