# Alloy K UNS K94610: Properties and Applications

## Introduction to Alloy K UNS K94610

Alloy K, designated as UNS K94610, is a specialized nickel-based superalloy known for its exceptional high-temperature strength and corrosion resistance. This alloy has found widespread use in demanding industrial applications where extreme conditions are present.

## Chemical Composition

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

– Nickel (Ni): Primary base element (approximately 63%)
– Chromium (Cr): 21-23%
– Iron (Fe): 5-7%
– Molybdenum (Mo): 5-7%
– Copper (Cu): 1.5-2.5%
– Aluminum (Al): 0.5-1.5%
– Titanium (Ti): 0.5-1.5%
– Carbon (C): ≤0.10%
– Manganese (Mn): ≤1.0%
– Silicon (Si): ≤0.50%

## Mechanical Properties

Alloy K exhibits impressive mechanical characteristics:

– Tensile Strength: 110-130 ksi (760-900 MPa)
– Yield Strength: 60-80 ksi (415-550 MPa)
– Elongation: 30-40%
– Hardness: 150-200 HB
– Creep Resistance: Excellent at temperatures up to 1800°F (980°C)

## Physical Properties

Key physical properties include:

– Density: 8.19 g/cm³ (0.296 lb/in³)
– Melting Range: 2300-2450°F (1260-1345°C)
– Thermal Expansion Coefficient: 7.2 µin/in-°F (13 µin/in-°C) at 70-1000°F
– Thermal Conductivity: 9.1 Btu·in/ft²·h·°F (15.7 W/m·K) at 70°F
– Electrical Resistivity: 45.5 µΩ·cm at 70°F

## Corrosion Resistance

Alloy K demonstrates outstanding resistance to various corrosive environments:

– Excellent resistance to oxidizing and reducing acids
– Superior performance in chloride-containing solutions
– Good resistance to stress corrosion cracking
– Maintains integrity in sulfur-containing atmospheres
– Resistant to pitting and crevice corrosion

## Heat Treatment

The alloy can be heat treated to optimize its properties:

– Annealing: 1900-2100°F (1040-1150°C) followed by rapid cooling
– Stress Relieving: 1200-1400°F (650-760°C) for 1-2 hours
– Age Hardening: Not typically required but can be performed at 1200-1400°F (650-760°C)

## Fabrication and Welding

Alloy K offers good fabrication characteristics:

– Can be readily formed using standard techniques
– Machinability similar to other nickel-based alloys
– Weldable using conventional methods (TIG, MIG, SMAW)
– Post-weld heat treatment recommended for critical applications

## Applications of Alloy K UNS K94610

This versatile alloy serves in numerous demanding applications:

### Chemical Processing Industry

– Reactor vessels and heat exchangers
– Pumps and valves for corrosive media
– Distillation columns and piping systems

### Power Generation

– Gas turbine components
– Heat recovery steam generators
– Flue gas desulfurization systems

### Oil and Gas

– Downhole equipment
– Subsea components
– Refinery processing units

### Aerospace

– Jet engine components
– Exhaust systems
– High-temperature fasteners

### Other Applications

– Nuclear reactor components
– Pollution control equipment
– Marine hardware

## Advantages Over Competing Materials

Alloy K offers several benefits compared to alternative