Monel K500
Monel K500 UNS N05500 is a nickel-copper alloy containing 63% nickel, 27.0-33.0% copper, 2.5% iron, 1.5% manganese, and small amounts of aluminum and titanium. Monel alloy K500 is known for its exceptional strength and durability, high resistance to corrosion and erosion, and excellent resistance to stress corrosion cracking in seawater and other harsh environments. Compared to Alloy 400, Alloy K500 has approximately three times the yield strength and approximately 2 times the tensile strength.
Monel 400
Monel 400 UNS N04400, on the other hand, is a nickel-copper alloy consisting of 63% nickel and 28.0-34.0% copper. Monel alloy 400 is slightly less strong and corrosion-resistant than Monel K500, but is still highly resistant to corrosion and retains its strength in high-temperature and high-stress applications. Monel 400 is commonly used in the marine and chemical processing industries for the manufacture of pipes, valves, and pumps.
Differences In Mechanical Properties
One major difference between Monel K500 and 400 is the strength of their mechanical properties. Due to the addition of aluminum and titanium, coupled with precipitation hardening, nickel alloy K500 is significantly stronger and harder than 400. This makes the K500 more resistant to fatigue and breakage, and better able to withstand high-stress environments. However, because K500 is tougher, it is also more difficult to machine and weld than 400.
Monel K500 and 400 Mechanical Properties
| Mechanical properties | Tensile, min, ksi[MPa] | Yield, min, ksi[MPa] | Elongation, %(min) |
| Monel 400 | 70[485] | 28[195] | 35 |
| Monel K500 | 160[1100] | 115[790] | 20 |
