Introduction
Two of the most important alloy systems in which iron and other elements form alloys are known as the Invar Alloys and Wrought Alloys. Invar Alloy finds its origin in 1893, when Charle Guillaume, a Swiss scientist, invented this alloy to decrease the expansion coefficient of metals while increasing their strength and ability to hold dimensional stability at variable temperatures. Wrought Alloys, on the other hand, are a group of iron-based alloys which are being used increasingly for construction and production purposes. This paper provides a comparative analysis of Invar Alloy and Wrought Alloy focusing on their characteristics, advantages, disadvantages and applications.
Characteristics and Composition
Invar Alloy is a very low coefficient of expansion difficult-to-cut alloy, which is a combination of iron and nickel. Invar Alloys usually have a composition of 36% nickel and a balance of iron. The chemical composition of Invar is not a fixed ratio as it can vary up to 4%, although the composition can vary depending on the manufacturer. The major component in Invar Alloy is nickel, which gives the alloy its properties of negligible expansion and makes it suitable for machining and welding.
Wrought Alloys, on the other hand, are a group of iron-based alloys that contain other metals such as chromium, molybdenum, vanadium, manganese and silicon. The composition of these alloys depends on the desired mechanical properties. The proportion of these metals in the alloy varies depending on their percentage. Chromium is the main component in wrought alloys, with its concentration typically ranging from 12% to 20%. The other elements, such as molybdenum, manganese and silicon, are present in much smaller amounts, usually below 2% for each component.
Advantages and Disadvantages
Invar Alloy offers excellent machinability and good corrosion resistance, along with low thermal conductivity and good electrical conductivity. The low coefficient of expansion makes Invar Alloy ideal for applications that requires dimensional stability over a wide range of temperatures. Invar Alloy can also be used in applications requiring localized magnetic shielding. The major disadvantages associated with Invar Alloys are its high cost and difficulty in cutting.
Wrought Alloys have many advantages over other metals, including good corrosion resistance, excellent strength and toughness, good fatigue strength, and excellent impact strength. In addition, wrought alloys have low thermal expansion, which makes them suitable for applications requiring reduced expansion. The main disadvantage of wrought alloys is its relatively high cost, especially when compared to other metals such as aluminum or stainless steel.
Applications
Invar Alloy is commonly used in medical/scientific instruments, aircraft components, and aerospace applications. It is also used in the electrical and electronic industries for transformers, wiring, power distribution, and other applications that require dimensional stability over a wide range of temperatures or the ability to shrink and expand elastically. In addition, Invar Alloy is used in the production of ultra-large aircraft engine turbine blades and other parts with special needs.
Wrought Alloys are extensively used in a wide range of applications, including automotive parts and components, aerospace components, pumps, valves and machine parts, as well as offshore and marine equipment. Wrought alloys are also used in construction and production applications, such as bridges, buildings, tunnels, pipelines and ships, due to their excellent mechanical properties, including good resistance to corrosion, excellent strength and excellent impact resistance.
Conclusion
In conclusion, Invar Alloy and Wrought Alloy are two alloy systems that have their own unique characteristics and applications. While Invar Alloy finds its primary use in medical/scientific instruments, aircraft components and aerospace applications, Wrought Alloys are used for a much wider range of applications, including automotive components, aerospace components, and offshore and marine equipment. In addition, Invar Alloy has low thermal expansion, good electrical and thermal conductivity, and good machinability, whereas Wrought Alloy has excellent corrosion resistance and impact strength. Finally, Invar Alloy is more expensive and difficult to cut than Wrought Alloy.
