# Alloy G-3 (UNS N06985) Properties and Applications
## Introduction to Alloy G-3 (UNS N06985)
Alloy G-3, also known as UNS N06985, is a nickel-chromium-iron-molybdenum alloy designed to offer superior resistance to a wide range of corrosive environments. This alloy is particularly known for its excellent performance in both oxidizing and reducing conditions, making it a popular choice for various industrial applications.
Keyword: Alloy G-3 UNS N06985
## Chemical Composition
The chemical composition of Alloy G-3 plays a crucial role in its corrosion resistance and mechanical properties. The primary elements include:
– Nickel (Ni): 44-47%
– Chromium (Cr): 21-23.5%
– Iron (Fe): 18-21%
– Molybdenum (Mo): 6-8%
– Copper (Cu): 1.5-2.5%
– Carbon (C): ≤0.015%
## Mechanical Properties
Alloy G-3 exhibits excellent mechanical properties, which contribute to its widespread use in demanding environments. Some key mechanical properties include:
– Tensile Strength: 690 MPa (100 ksi) min
– Yield Strength: 310 MPa (45 ksi) min
– Elongation: 30% min
– Hardness: ≤100 HRB
## Corrosion Resistance
One of the standout features of Alloy G-3 is its exceptional corrosion resistance. It performs well in:
– Sulfuric acid environments
– Phosphoric acid solutions
– Hydrochloric acid media
– Mixed acid environments containing oxidizing salts
– Seawater and chloride-containing solutions
## Applications of Alloy G-3
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 in aggressive environments
– Piping systems for acid transportation
### Oil and Gas Industry
– Downhole equipment in sour gas wells
– Components in flue gas desulfurization systems
– Offshore platform components exposed to seawater
### Pollution Control Equipment
– Scrubbers and stack liners
– Waste treatment systems
– Flue gas cleaning systems
## Fabrication and Welding
Alloy G-3 can be readily fabricated using standard techniques. Some important considerations include:
– Hot working should be performed between 2100°F (1149°C) and 1600°F (871°C)
– Cold working requires intermediate annealing
– Welding can be performed using matching filler metal (ERNiCrMo-10)
– Post-weld heat treatment is generally not required
## Conclusion
Alloy G-3 (UNS N06985) offers an excellent balance of corrosion resistance, mechanical properties, and fabricability, making it a versatile material for challenging industrial applications. Its ability to withstand both oxidizing and reducing environments ensures reliable performance in some of the most corrosive conditions encountered in chemical processing, oil and gas, and pollution control industries.