Product Focus – Monel Alloy 400

For those seeking a low-cost, reliable alloy that still retains many of the benefits of its better-known and more expensive cousins, we think MONEL 400 alloy is definitely worth a look.

MONEL 400 alloy has been around for many years and remains a versatile choice. It's rare to see an alloy dominate so many industry applications for so long, and like another classic alloy, INCONEL 625, MONEL 400 alloy has bucked the trend. However, this adaptable material is even older than the popular INCONEL 625-it was introduced as early as 1905. Its popularity is due to its key feature: a high copper content of 28-34%, which distinguishes it from commercially pure nickel, while retaining many of the properties similar to Nickel 200/Nickel 201.

MONEL 400 has remained dominant because it is used in many fields, including marine and chemical processing. It has been used in petroleum distillation tower internals, fasteners and fittings, pumps and valve trim for more than 100 years. Other applications include process vessels, heat exchanger pipes and gasoline tanks.

Due to its properties, it is well suited for high-risk environments, such as the explosives industry and the pulp/paper industry. It is also used in rocket technology, which is particularly hot right now - we wonder if Tim Peake (whose trip to space made our list of favorite things in 2015) is wearing this alloy on the space station right now!

Applications at extreme temperatures
What makes this alloy so versatile? Because it has high strength and toughness over a wide temperature range. On the one hand, due to its strength and hardness, this alloy is well suited to sub-zero environments and does not undergo a ductile-brittle transition even at the extremely low temperatures of liquid hydrogen.

On the other hand, in oxidizing atmospheres, it works just as well, even at temperatures of up to 1,000 degrees Fahrenheit (about 574 degrees Celsius). In reducing environments, it can even be used at higher temperatures.

Corrosion resistance
Besides being particularly well suited to extreme temperatures, this alloy also has good corrosion resistance, which is undoubtedly a welcome quality. It has proven to be more resistant to attack by oxidizing elements than high copper alloys. For this reason, it remains popular in marine applications, as it has an extremely low corrosion rate in flowing seawater. It also resists stress corrosion cracking and pitting in most freshwater and industrial waters.

Another advantage is that it provides excellent corrosion resistance in hydrofluoric acid environments, even in all concentrations up to the boiling point. It is considered to be one of the most corrosion resistant of all commonly used engineering alloys.

Fabrication Process
MONEL 400 alloy is a solid solution alloy that can only be hardened by cold working. But it can also be hot worked or cold worked and then annealed. The material remains bright and does not change color when heated and cooled in a reducing atmosphere. Heat treatment is required to obtain significant strength and toughness, whether hot or cold worked.

It is easily fabricated by standard processes, which means that it can be produced with a wide range of mechanical properties, which increases its versatility. It is also relatively easy to machine and can be joined to itself or to dissimilar alloys using most conventional welding processes.

Detailed technical specifications for this alloy can be found on the dedicated page on our website. To discuss your requirements please contact a member of our sales team.