# Alloy G-3 UNS N06985: Properties and Applications
## Introduction to Alloy G-3 UNS N06985
Alloy G-3, also known by its UNS designation N06985, is a nickel-chromium-iron-molybdenum alloy that offers excellent resistance to a wide range of corrosive environments. This alloy was specifically developed to provide superior performance in highly corrosive conditions where other materials might fail.
## Chemical Composition
The chemical composition of Alloy G-3 plays a crucial role in its corrosion resistance properties:
– Nickel (Ni): 44% (min)
– Chromium (Cr): 21-23.5%
– Iron (Fe): 18-21%
– Molybdenum (Mo): 6-8%
– Copper (Cu): 1.5-2.5%
– Niobium (Nb): 0.5% (max)
– Carbon (C): 0.015% (max)
## Key Properties of Alloy G-3
Alloy G-3 exhibits several important properties that make it valuable for industrial applications:
### Corrosion Resistance
The alloy demonstrates outstanding resistance to:
– Sulfuric acid environments
– Phosphoric acid
– Hydrochloric acid
– Nitric acid
– Various organic acids
### Mechanical Properties
Typical mechanical properties at room temperature include:
– Tensile Strength: 690 MPa (100 ksi)
– Yield Strength: 310 MPa (45 ksi)
– Elongation: 40%
### Thermal Properties
Alloy G-3 maintains good mechanical properties at elevated temperatures:
– Operating temperature range: -196°C to 400°C (-320°F to 750°F)
– Good thermal stability
## Applications of Alloy G-3 UNS N06985
Due to its unique combination of properties, Alloy G-3 finds applications in various industries:
### Chemical Processing Industry
– Reactors and vessels handling corrosive chemicals
– Heat exchangers
– Piping systems
### Oil and Gas Industry
– Downhole components
– Wellhead equipment
– Flowlines in sour gas service
### Pollution Control Equipment
– Flue gas desulfurization systems
– Scrubbers
– Waste treatment facilities
### Other Applications
– Pharmaceutical processing equipment
– Pulp and paper industry components
– Seawater handling systems
## Fabrication and Welding Considerations
Alloy G-3 can be fabricated using standard techniques, but requires some special considerations:
### Forming
The alloy can be hot or cold worked, though it work hardens more rapidly than standard austenitic stainless steels.
### Welding
Recommended welding methods include:
– Gas tungsten arc welding (GTAW)
– Gas metal arc welding (GMAW)
– Shielded metal arc welding (SMAW)
Post-weld heat treatment is generally not required for Alloy G-3.
## Comparison with Similar Alloys
Alloy G-3 offers several advantages over similar materials:
Keyword: Alloy G-3 UNS N06985
– Better resistance to sulfuric acid than Alloy 625
– Superior performance in phosphoric acid compared to Alloy C-276
– More cost-effective than some higher-nickel alloys for certain applications
## Conclusion
Alloy G-3 UNS N06985 provides an excellent balance of corrosion resistance, mechanical properties, and cost-effectiveness for demanding industrial applications. Its versatility makes it a preferred choice for equipment exposed to highly corrosive environments across multiple industries. When selecting materials for aggressive chemical service, Alloy G-3 should be considered as a reliable option that can extend equipment life and reduce maintenance costs.