UNS R30188 Specification and Application Guidelines

# UNS R30188 Specification and Application Guidelines

## Introduction to UNS R30188

UNS R30188 is a high-performance cobalt-based alloy that offers exceptional resistance to wear, corrosion, and high temperatures. This material is part of the Stellite family of alloys, which are renowned for their durability in extreme environments.

## Chemical Composition

The chemical composition of UNS R30188 plays a crucial role in its performance characteristics:

Element | Percentage
Cobalt (Co) | Balance
Chromium (Cr) | 28-32%
Tungsten (W) | 4-6%
Carbon (C) | 1.0-1.4%
Nickel (Ni) | ≤3.0%
Iron (Fe) | ≤3.0%
Silicon (Si) | ≤1.0%
Manganese (Mn) | ≤1.0%

## Mechanical Properties

UNS R30188 exhibits impressive mechanical properties that make it suitable for demanding applications:

– Hardness: 40-45 HRC (as cast)
– Tensile Strength: 1000-1200 MPa
– Yield Strength: 700-900 MPa

Keyword: uns r30188

– Elongation: 1-3%

## Heat Treatment

Proper heat treatment enhances the performance of UNS R30188:

The recommended heat treatment for UNS R30188 involves solution annealing at 1200-1250°C (2192-2282°F) followed by rapid cooling. This process helps achieve optimal hardness and corrosion resistance while maintaining dimensional stability.

## Applications

UNS R30188 finds extensive use in various industries due to its unique properties:

Industrial Applications

  • Valve seats and guides

  • Pump components

  • Bearings and bushings

  • Cutting tools and dies

Aerospace Applications

  • Turbine blades

  • Combustion chamber components

  • Exhaust system parts

## Machining and Fabrication

Working with UNS R30188 requires special considerations:

Due to its high hardness and work-hardening characteristics, UNS R30188 should be machined using carbide tools at moderate speeds with ample coolant. Grinding is often preferred over conventional machining for finishing operations.

## Welding Considerations

Proper welding techniques are essential for maintaining the alloy’s properties:

  • Use matching filler metal (Stellite 6 or similar)

  • Preheat to 300-400°C (572-752°F)

  • Employ low heat input techniques (TIG preferred)

  • Perform post-weld stress relief when necessary

## Corrosion Resistance

UNS R30188 offers excellent resistance to:

  • Oxidation at high temperatures

  • Sulfuric and phosphoric acid environments

  • Seawater and chloride-containing solutions

  • Wear-corrosion combinations

## Conclusion

UNS R30188 represents a premium choice for applications requiring exceptional wear resistance combined with good corrosion protection at elevated temperatures. Its balanced composition and versatile properties make it suitable for critical components across multiple industries. Proper selection, fabrication, and maintenance practices will ensure optimal performance and longevity of components made from this advanced cobalt alloy.