# Alloy G-3 (UNS N06985) Properties and Applications
## Introduction to Alloy G-3
Alloy G-3, also known by its UNS designation N06985, is a nickel-chromium-iron-molybdenum alloy with enhanced corrosion resistance. This alloy was specifically developed to offer superior performance in highly corrosive environments, particularly those containing sulfuric acid and other aggressive chemicals.
## Chemical Composition
The chemical composition of Alloy G-3 plays a crucial role in its exceptional properties:
Nickel (Ni): 44% minimum
Chromium (Cr): 21-23.5%
Iron (Fe): 18-21%
Molybdenum (Mo): 6-8%
Copper (Cu): 1.5-2.5%
Other elements: Small amounts of tungsten, cobalt, and niobium
## Key Properties of Alloy G-3
Corrosion Resistance
Alloy G-3 exhibits outstanding resistance to a wide range of corrosive media, including sulfuric, phosphoric, and nitric acids. Its performance is particularly notable in environments containing chlorides and other halides.
Mechanical Properties
The alloy maintains good mechanical strength at both ambient and elevated temperatures, with typical tensile strength ranging from 690 to 830 MPa (100 to 120 ksi).
Fabrication Characteristics
Alloy G-3 can be readily fabricated using standard techniques, including hot and cold working, machining, and welding. Its weldability is particularly good compared to many other corrosion-resistant alloys.
## Applications of Alloy G-3
Chemical Processing Industry
Alloy G-3 is widely used in chemical processing equipment such as reactors, heat exchangers, and piping systems where resistance to sulfuric acid and other aggressive chemicals is required.
Pollution Control Systems
The alloy finds applications in flue gas desulfurization systems and other pollution control equipment due to its resistance to acidic environments.
Oil and Gas Industry
In the oil and gas sector, Alloy G-3 is used for components exposed to sour gas environments containing hydrogen sulfide and carbon dioxide.
Keyword: Alloy G-3 UNS N06985
Pharmaceutical Industry
The pharmaceutical industry utilizes Alloy G-3 for equipment requiring high purity and corrosion resistance in processing various chemical compounds.
## Comparison with Similar Alloys
Compared to Alloy C-276 (UNS N10276), Alloy G-3 offers better resistance to sulfuric acid environments but may not perform as well in highly oxidizing conditions. When compared to Alloy 625 (UNS N06625), Alloy G-3 typically shows superior resistance to localized corrosion in chloride-containing environments.
## Conclusion
Alloy G-3 (UNS N06985) represents an excellent choice for applications requiring resistance to sulfuric acid and other aggressive chemicals. Its balanced combination of corrosion resistance, mechanical properties, and fabricability makes it a valuable material across multiple industries. When selecting materials for corrosive environments, engineers should carefully consider Alloy G-3 as a potential solution for challenging applications.