What are the disadvantages of Monel?
Monel is an alloy of nickel and copper that was first developed for commercial use in 1905. It is highly regarded for its excellent resistance to corrosion and high temperatures, making it particularly useful in the marine and chemical processing industries.
Monel alloys are commonly used in chemical plant equipment because of their strong resistance to chemical corrosion. They are also used in the aerospace industry. Products made with Monel alloys (especially before the advent of stainless steel) include heat exchangers, screw machine products, wind instruments, piping systems, fuel and water tanks, kitchen sinks, and roofing.
Advantages of Monel Alloys:
There are many Monel alloys to choose from. Prior to the 1950s, they were the "go-to" choice for many vital industries. It can also be easily welded, brazed, and soldered. This is because of its:
High corrosion resistance to acids and bases;
High mechanical strength;
Good ductility (easy to form and shape);
Alkali resistance;
Relatively low cost;
Available in different forms, including hot-rolled and cold-rolled sheets, plates, bars, rods, and tubes
Attractive appearance and finish, including a gray-green patina similar to copper;
Disadvantages of Monel Alloys:
While Monel alloys have many advantages, it is far from a perfect metal. Machinability of these alloys is poor, as they tend to work harden quickly. What's more:
While surface discoloration in the form of patina may be attractive in some cases, it can be problematic in other situations.
While it is corrosion resistant, it can become pitted if exposed to salt water.
While it resists corrosion in many situations, it can corrode when exposed to certain substances. For example, nitric oxide, nitrous acid, sulfur dioxide, and hypochlorites are all substances that can corrode monel.
The presence of monel can cause galvanic corrosion. In other words, if aluminum, zinc, or iron is used as a fastener with monel and then exposed to certain conditions, the metal fastener will corrode quickly.
