Alloy 330 UNS N08330: Properties and Applications

# Alloy 330 UNS N08330: Properties and Applications

## Introduction to Alloy 330 UNS N08330

Alloy 330, also known as UNS N08330, is a nickel-iron-chromium austenitic alloy designed for high-temperature applications. This material offers excellent resistance to oxidation and carburization, making it a popular choice in various industrial sectors.

## Chemical Composition

The chemical composition of Alloy 330 plays a crucial role in its performance characteristics:

– Nickel (Ni): 34-37%
– Chromium (Cr): 17-20%
– Iron (Fe): Balance
– Silicon (Si): 0.75-1.50%
– Manganese (Mn): ≤2.00%
– Carbon (C): ≤0.08%
– Phosphorus (P): ≤0.03%
– Sulfur (S): ≤0.03%

## Physical Properties

Alloy 330 exhibits several notable physical properties:

– Density: 8.08 g/cm³ (0.292 lb/in³)
– Melting Range: 1371-1427°C (2500-2600°F)
– Electrical Resistivity: 1.02 μΩ·m
– Thermal Conductivity: 12.5 W/m·K (at 100°C)
– Coefficient of Thermal Expansion: 14.4 μm/m·K (20-100°C)

## Mechanical Properties

The mechanical properties of Alloy 330 make it suitable for demanding applications:

– Tensile Strength: 550 MPa (80 ksi) min
– Yield Strength: 240 MPa (35 ksi) min
– Elongation: 30% min
– Hardness: ≤90 HRB (annealed condition)

## Corrosion Resistance

Alloy 330 demonstrates excellent resistance to:

– Oxidation at high temperatures
– Carburization in hydrocarbon environments
– Sulfidation in sulfur-bearing atmospheres
– Nitriding in nitrogen-rich environments

## High-Temperature Performance

One of the key advantages of Alloy 330 is its performance at elevated temperatures:

– Continuous service: Up to 1150°C (2100°F)
– Intermittent service: Up to 1185°C (2165°F)
– Excellent resistance to thermal cycling
– Good creep strength at high temperatures

## Fabrication and Welding

Alloy 330 can be readily fabricated using standard techniques:

– Hot working: 870-1230°C (1600-2250°F)
– Cold working: Requires intermediate annealing
– Welding: Can be welded using common methods (TIG, MIG, SMAW)
– Post-weld heat treatment: Generally not required

## Heat Treatment

Proper heat treatment enhances the properties of Alloy 330:

– Annealing: 1038-1121°C (1900-2050°F) followed by rapid cooling
– Stress relieving: 870-925°C (1600-1700°F) for 1-2 hours

## Applications of Alloy 330

Alloy 330 finds use in numerous industrial applications:

### Heat Treatment Industry

– Furnace components
– Retorts and muffles
– Heat exchanger tubes
– Radiant tubes

### Petrochemical Industry

– Reformer tubes
– Catalyst support grids
– Pyrolysis equipment
– Flare tips

### Power Generation

– Combustion chambers
– Heat recovery systems
– Boiler components

### Other Applications

– Food processing equipment
– Semiconductor manufacturing
– Nuclear fuel processing
– Chemical processing

## Advantages Over Other Alloys

Alloy 330 offers several advantages compared to similar materials:

– Better oxidation resistance than 304 and 310 stainless steels
– Superior carburization resistance compared to many nickel alloys
– More cost-effective than some high-nickel alloys