Monel K-500 is an age-hardenable monel alloy
• UNS N05500
• Other common names: Alloy K500
Monel K500 is a precipitation-hardenable nickel-copper alloy that combines the excellent corrosion resistance of Monel 400 with the added advantages of higher strength and hardness. These amplified properties, strength and hardness are achieved by the addition of aluminum and titanium to the nickel-copper matrix and by a heat treatment used to achieve precipitation (commonly referred to as age hardening or solutionizing). When in the age-hardened condition, Monel K-500 is more susceptible to stress corrosion cracking than Monel 400 in certain environments. Alloy K-500 has approximately three times the yield strength and double the tensile strength compared to Alloy 400. Additionally, it can be further strengthened by cold working prior to precipitation hardening. This nickel alloy is spark resistant and nonmagnetic to -200°F. However, a magnetic layer can form on the surface of the material during processing. The aluminum and copper can be selectively oxidized during heating, leaving a nickel-rich magnetic film on the exterior. Pickling or bright dipping in acid can remove this magnetic film and restore nonmagnetic properties.
What forms of Monel K-500 are available?
• Bars
• Plates
Corrosion Resistant Monel K-500
The corrosion resistance of alloy K-500 is essentially equal to that of alloy 400, except that in the age-hardened condition, nickel alloy K-500 has a greater tendency to stress corrosion cracking in certain environments. Monel K-500 has been found to resist sour gas environments. The combination of high velocity scorching hot water and very low rates of high intensity corrosion makes alloy K-500 particularly suitable for centrifugal pump shafts in marine service. In stagnant or slowly moving seawater, scaling may occur, followed by pitting, but this pitting slows down after a fairly rapid initial attack.
Monel K500 chemical composition, %
Nickel (with cobalt): ≥63.0
Carbon: ≤0.25
Manganese: ≤1.5
Iron: ≤2.0
Sulfur: ≤ 0.01
Silicon: ≤0.5
Copper: 27.0 -33.0
Aluminum: 2.30 - 3.15
Titanium: 0.35 - 0.85
What are the characteristics of Monel K500?
• Corrosion resistance in a wide range of marine and chemical environments. From pure water to non-oxidizing inorganic acids, salts and alkalis.
• Excellent resistance to high-velocity seawater
• Resistance to sour gas environments
• Excellent mechanical properties from sub-zero temperatures to about 480°C
• Non-magnetic alloy
In what applications is Monel K-500 used?
• Sour gas service applications
• Oil and gas production safety lifts and valves
• Oil well tools and instruments such as drill collars
• Oil well industry
• Doctor blades and scrapers
• Chains, cables, springs, valve trim, marine fasteners
• Pump shafts and impellers in marine service
