STELLITE® Alloy 20 Product Introduction
STELLITE® Alloy 20 is a cobalt-based alloy known for its exceptional resistance to wear, corrosion, and high temperatures. This article provides a detailed introduction to STELLITE® Alloy 20, covering its chemical composition, mechanical properties, performance at different temperatures, industry applications, shapes and sizes, production standards, welding and processing capabilities, advantages and disadvantages, and comparisons with similar alloys.
Chemical Composition
STELLITE® Alloy 20 is primarily composed of cobalt, chromium, tungsten, and carbon, with additional elements for enhanced properties.
| Element | Composition (%) |
|---|---|
| Cobalt (Co) | 32.0 – 38.0 |
| Chromium (Cr) | 19.0 – 21.0 |
| Tungsten (W) | 2.0 – 3.0 |
| Carbon (C) | 0.15 – 0.35 |
| Nickel (Ni) | 2.0 max |
| Iron (Fe) | 3.0 max |
| Manganese (Mn) | 1.0 max |
| Silicon (Si) | 1.0 max |
| Phosphorus (P) | 0.03 max |
| Sulfur (S) | 0.03 max |
Mechanical Properties
STELLITE® Alloy 20 exhibits excellent mechanical properties suitable for high-wear applications:
| Property | Value |
|---|---|
| Tensile Strength, ksi (MPa) | 105 (725) min |
| Yield Strength (0.2% offset), ksi (MPa) | 45 (310) min |
| Elongation (% in 2 inches) | 30 min |
| Hardness, Rockwell C (HRC) | 25 – 35 |
Performance Characteristics
STELLITE® Alloy 20 offers outstanding performance in severe conditions:
- Wear Resistance: Exceptional resistance to abrasion, erosion, and metal-to-metal wear, making it ideal for high-stress wear environments.
- Corrosion Resistance: Excellent resistance to oxidation and corrosion in high-temperature environments, including acids and alkalis.
- High Temperature Strength: Maintains high strength and hardness at elevated temperatures, up to approximately 1200°F (650°C).
Industry Applications
STELLITE® Alloy 20 is widely used across various industries for its wear and corrosion resistance properties:
| Industry Sector | Applications |
|---|---|
| Aerospace | Bearing surfaces, valve components, and turbine blades requiring high wear resistance and durability. |
| Oil and Gas | Pump components, valve seats, and drilling tools exposed to abrasive environments and corrosive fluids. |
| Power Generation | Boiler components, steam turbine seals, and high-wear parts in power plant equipment. |
| Industrial Machinery | Cutting tools, extrusion dies, and wear plates in manufacturing equipment. |
Shapes and Sizes
STELLITE® Alloy 20 is available in various forms and sizes to meet specific application requirements:
- Forms: Sheets, plates, bars, tubes, and custom shapes.
- Sizes: Thickness ranging from 0.025 inches to 1.000 inches (0.64mm to 25.4mm), diameter ranging from 0.25 inches to 6.0 inches (6.35mm to 152.4mm).
Production Standards
STELLITE® Alloy 20 complies with industry standards for quality and performance:
| Product Form | Shapes Available | Sizes Available | Production Standards |
|---|---|---|---|
| Bars | Round bars, square bars | Diameter: 0.25″ – 6.0″ (6.35mm – 152.4mm) | ASTM A732 |
| Plates/Sheets | Plates, Sheets | Thickness: 0.025″ – 1.000″ (0.64mm – 25.4mm) | ASTM A732 |
| Welding Rods | Rods | Diameter: 0.125″ – 0.500″ (3.18mm – 12.7mm) | AWS A5.13 |
Welding and Processing
STELLITE® Alloy 20 offers good weldability and machinability:
- Welding: Can be welded using conventional methods such as TIG and MIG welding with preheating and post-weld heat treatment to maintain properties.
- Processing: Machinable using carbide tooling, although care is needed due to its high cobalt content.
Advantages and Disadvantages
| Aspect | Details |
|---|---|
| Advantages | High wear resistance, excellent strength at elevated temperatures, good corrosion resistance, and ease of fabrication. |
| Disadvantages | Higher cost compared to conventional materials, requires specialized machining and welding techniques due to high cobalt content. |
Similar Alloys
| Alloy Name | Comparison |
|---|---|
| STELLITE® Alloy 6 | Higher cobalt content, offering superior wear resistance and hardness compared to Alloy 20. |
Comparison of Similar Alloys
| Property/Feature | STELLITE® Alloy 20 | STELLITE® Alloy 6 |
|---|---|---|
| Cobalt Content (%) | 32.0 – 38.0 | 54.0 – 62.0 |
| Chromium Content (%) | 19.0 – 21.0 | 27.0 – 32.0 |
| Tungsten Content (%) | 2.0 – 3.0 | 8.0 – 10.0 |
| Hardness, Rockwell C (HRC) | 25 – 35 | 48 – 55 |
| Applications | Valve components, extrusion dies | Aerospace components, turbine blades |
This comprehensive article provides an in-depth introduction to STELLITE® Alloy 20, highlighting its chemical composition, mechanical properties, performance characteristics, industry applications, available forms and sizes, production standards, welding and processing capabilities, as well as advantages, disadvantages, and comparisons with similar alloys. Engineers and professionals seeking durable materials for high-wear and corrosion resistance applications will find this information valuable for selecting the appropriate alloy to meet their specific needs.