# Alloy HR160 UNS N12160: Properties and Applications

## Introduction to Alloy HR160 UNS N12160

Alloy HR160, also known by its UNS designation N12160, is a nickel-chromium-cobalt superalloy designed for high-temperature applications. This advanced material combines excellent oxidation resistance with superior strength at elevated temperatures, making it a preferred choice for demanding industrial environments.

## Chemical Composition

The unique properties of Alloy HR160 stem from its carefully balanced chemical composition:

– Nickel (Ni): Primary base element (approximately 37%)
– Chromium (Cr): 28% for oxidation resistance
– Cobalt (Co): 29% for high-temperature strength
– Silicon (Si): 2.5% for improved oxidation resistance
– Titanium (Ti): 0.5% for precipitation strengthening
– Other elements: Small amounts of carbon, manganese, and iron

## Mechanical Properties

Alloy HR160 exhibits impressive mechanical characteristics:

– Tensile Strength: 110-130 ksi (760-900 MPa) at room temperature
– Yield Strength: 70-90 ksi (480-620 MPa)
– Elongation: 30-40% in 2 inches
– Hardness: 200-250 HB
– Creep Resistance: Excellent performance at temperatures up to 1800°F (982°C)

## Physical Properties

Key physical properties of Alloy HR160 include:

– Density: 0.296 lb/in³ (8.19 g/cm³)
– Melting Range: 2400-2500°F (1315-1371°C)
– Thermal Expansion Coefficient: 8.5 µin/in-°F (15.3 µm/m-°C) from 70-1000°F
– Thermal Conductivity: 90 Btu-in/hr-ft²-°F (13 W/m-K) at 70°F
– Electrical Resistivity: 550 µΩ-cm at 70°F

## Key Advantages

Alloy HR160 offers several distinct advantages:

– Exceptional resistance to oxidation and carburization
– Good resistance to sulfidation in reducing environments
– High creep-rupture strength at elevated temperatures
– Excellent thermal fatigue resistance
– Good fabricability and weldability compared to other superalloys

## Industrial Applications

Due to its unique combination of properties, Alloy HR160 finds use in numerous demanding applications:

### Petrochemical Industry

– Ethylene pyrolysis furnace components
– Reformer tubes and pigtails
– Transfer line exchangers
– Waste heat recovery systems

### Power Generation

– Gas turbine combustion components
– Heat exchangers in advanced power plants
– Boiler tubes in waste-to-energy facilities

### Industrial Furnaces

– Radiant tubes and muffles
– Roller hearth furnace components
– Heat treatment fixtures
– Annealing furnace hardware

### Other Applications

– Chemical processing equipment
– Nuclear reactor components
– Aerospace engine parts
– High-temperature fasteners

## Fabrication and Welding

Alloy HR160 can be successfully fabricated using standard techniques:

– Machining: Requires rigid setups and positive feeds
– Forming: Hot forming recommended above 1800°F (982°C)
– Welding: Gas tungsten arc welding (GTAW) preferred
– Heat Treatment: Solution annealing at 2100°F (1149°C) followed by rapid cooling

## Comparison with Other Alloys

Compared to similar high-temperature alloys:

– Better oxidation resistance than Alloy 800H/HT
– Superior carburization resistance to Alloy 617
– Higher creep strength than Alloy 230 at intermediate temperatures
– More cost-effective than some cobalt-based superalloys

## Maintenance Considerations

For optimal performance:

– Avoid thermal cycling beyond design limits
– Prevent contamination during fabrication
– Use compatible gasket materials