Monel 400 vs Monel K500 – What’s the Difference

Monel 400 vs Monel K500

If you’re in the market for a high-performance, corrosion-resistant alloy, you may come across Monel. This nickel-copper alloy can be found in various applications, from marine engineering, oil and gas production, chemical processing, and aerospace. But did you know that there are two different types of Monel? In this blog post, we’ll explore the difference between Monel 400 and Monel K500 and help you decide which is right for your needs.

Difference Between Monel 400 and Monel K500


The main difference between the Monel 400 and Monel K500 is their composition. Monel 400 is a nickel-copper alloy, containing between 63-70% nickel and 30-34% copper, along with trace amounts of iron, manganese, and silicon. Monel K500, on the other hand, contains approximately 65% nickel, 30% copper, 2.5% aluminium, and small amounts of titanium and iron. Adding aluminium to Monel K500 provides even greater strength and hardness than Monel 400.

Corrosion Resistance

Monel 400 and Monel K500 are highly corrosion-resistant, especially in marine environments where saltwater exposure can be particularly corrosive. Monel 400 has excellent resistance to chloride-induced stress corrosion cracking, while Monel K500 provides even greater resistance to seawater corrosion, making it ideal for applications such as propeller shafts and pump shafts.

Mechanical Properties

While both Monel 400 and Monel K500 are strong and durable alloys, Monel K500 has higher strength and hardness than Monel 400. Monel K500 can be hardened by cold working or precipitation hardening, while Monel 400 cannot be strengthened similarly. However, Monel K500 has lower ductility and is more difficult to form and machine than Monel 400.


The choice between Monel 400 and Monel K500 largely depends on the specific application and environment in which the alloy will be used. Monel 400 is well-suited to marine engineering, chemical processing, and paper production applications, where corrosion resistance is important. Monel K500 is often used in the aerospace industry and seawater environments, where its strength and corrosion resistance make it an ideal choice for propeller and pump shafts.


Finally, cost is a factor to consider when choosing between the Monel 400 and Monel K500. Monel K500 is more expensive than Monel 400 due to its higher strength and relatively low availability. If cost is a major factor in your decision, Monel 400 may be the better choice.


In conclusion, Monel 400 and Monel K500 are excellent nickel-copper alloys with unique properties and advantages. While the Monel 400 provides good corrosion resistance and is more readily available at a lower cost than the Monel K500, the Monel K500 offers even greater strength and corrosion resistance, making it the preferred choice in certain applications. When in doubt, consulting with a materials expert can help you determine the best option for your needs.



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