Stellite12 UNS R30012 Alloy Properties and Applications

# Stellite12 UNS R30012 Alloy Properties and Applications

## Introduction to Stellite12 UNS R30012

Stellite12, also known as UNS R30012, is a cobalt-based alloy renowned for its exceptional wear resistance, corrosion resistance, and high-temperature strength. This alloy belongs to the family of Stellite alloys, which are widely used in demanding industrial applications where durability and performance are critical.

## Chemical Composition

The chemical composition of Stellite12 UNS R30012 plays a crucial role in its performance characteristics:

– Cobalt (Co): Primary base element
– Chromium (Cr): 28-32%
– Tungsten (W): 7-9.5%
– Carbon (C): 1.2-1.7%
– Nickel (Ni): 2-4%
– Iron (Fe): ≤3%
– Silicon (Si): ≤2%
– Manganese (Mn): ≤1%

## Mechanical Properties

Stellite12 exhibits impressive mechanical properties that make it suitable for challenging environments:

– Hardness: 40-45 HRC (Rockwell C scale)
– Tensile Strength: 1000-1200 MPa
– Yield Strength: 700-900 MPa
– Elongation: 1-3%
– Density: 8.4 g/cm³

## Physical Properties

The physical characteristics of Stellite12 contribute to its performance:

– Melting Range: 1290-1425°C (2354-2597°F)
– Thermal Conductivity: 14.6 W/m·K
– Coefficient of Thermal Expansion: 12.3 μm/m·°C (20-100°C)
– Electrical Resistivity: 0.92 μΩ·m

## Key Features and Advantages

Stellite12 UNS R30012 offers several notable advantages:

– Excellent wear resistance in both abrasive and adhesive wear conditions
– Good corrosion resistance in various environments
– Maintains hardness and strength at elevated temperatures
– Superior galling resistance
– Good machinability in annealed condition
– Can be welded using appropriate techniques

## Applications of Stellite12 UNS R30012

Due to its unique combination of properties, Stellite12 finds applications in numerous industries:

### Oil and Gas Industry

– Valve components (seats, stems, and trim)
– Downhole tools
– Pump components
– Wear plates

### Power Generation

– Turbine components
– Valve seats and guides
– Bushing applications
– Wear-resistant coatings

### Automotive and Aerospace

– Exhaust valves
– Valve seat inserts
– Wear-resistant components

### Industrial Applications

– Cutting tools
– Bearing surfaces
– Wear plates for mining equipment
– Food processing equipment

## Fabrication and Processing

Stellite12 can be processed using various methods:

– Casting: Suitable for complex shapes and components
– Powder Metallurgy: For producing near-net shapes
– Welding: Used for hardfacing and repair applications
– Machining: Best performed in annealed condition with carbide tools

## Comparison with Other Stellite Alloys

While Stellite12 offers excellent properties, it’s important to understand how it compares to other Stellite alloys:

– Higher carbon content than Stellite6, providing better wear resistance
– Lower chromium content than Stellite21, resulting in slightly reduced corrosion resistance
– Better machinability than some higher-hardness Stellite grades
– More cost-effective than some premium Stellite alloys while maintaining good performance

## Maintenance and Care

To maximize the performance of Stellite12 components:

– Avoid thermal shock during operation
– Use proper lubrication in sliding applications
– Follow recommended machining parameters
– Store in dry conditions to prevent surface oxidation

## Conclusion

Stellite12 UNS R30012 is a versatile cobalt-based alloy that offers an excellent balance of wear resistance, corrosion resistance, and high-temperature performance.