Why is Monel expensive?
The main disadvantage of Monel compared to many other metals is its cost. This is because it is a series of nickel-based alloys containing up to 67% nickel. Nickel is one of the most expensive single elements used to produce corrosion-resistant metals, and its price can also be quite volatile.
For some applications, superduplex stainless steels can be replaced with Monel alloys, which offer similar strength levels but cost significantly less. Super duplex stainless steel has good corrosion resistance in seawater and many acids. However, the operating temperature range of superduplex stainless steels is much more limited than that of Monel grades. Therefore, if the intended application is to operate at temperatures below -50 degrees Celsius or above 250 degrees Celsius, this may not be a suitable alternative.
So-called "super-austenitic" stainless steels, such as Alloy 254, can match the cryogenic operating range of Monel grades but are much less strong. High-strength stainless steels such as Nit50 can match the strength levels and low-temperature operating ranges, but do not match the corrosion resistance levels of Monel.
Although stainless steel and some other nickel-based grades (such as Alloy 825) offer significant cost savings over Monel grades, they do not compete with Monel at lower and higher temperatures and in the very harsh environments found within the chemical processing industry. Alloy properties are comparable. and gas and marine applications.
