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What you should know about Monel K500?

What is Monel K500?

Monel K500 is a precipitation-hardenable nickel-copper alloy that combines the excellent corrosion resistance characteristic of Monel 400 with the added advantage of greater strength and hardness. These amplified properties, strength and hardness, are obtained by adding aluminum and titanium to the nickel-copper base and by a thermal processing used to effect precipitation, typically called age hardening or aging.

When in the age-hardened condition, Monel K-500 has a greater tendency toward stress-corrosion cracking in some environments than Monel 400. Alloy K-500 has approximately three times the yield strength and double the tensile strength when compared with alloy 400. Plus, it can be further strengthened by cold working prior to precipitation hardening. The strength of this nickel steel alloy is maintained to 1200° F but stays ductile and tough down to temperatures of 400° F. Its melting range is 2400-2460° F.

This nickel alloy is spark resistant and non-magnetic to -200° F. However, it is possible to develop a magnetic layer on the surface of the material during processing. Aluminum and copper may be selectively oxidized during heating, leaving a magnetic nickel rich film on the outside. Pickling or bright dipping in acid can remove this magnetic film and restore the non-magnetic properties.

What is the difference between Monel and Inconel?

The fundamental difference. Both Monel and Inconel have nickel as their primary metal. However, Monel has copper and Inconel has Chromium. To better distinguish the difference between these two, we need to address the strength of their dual-primary ingredient.

What is the difference between Monel 400 and K500?

Monel 400 is a solid solution strengthened alloy, Monel K-500 is a precipitation strengthened alloy. The overall performance of K-500 is better than 400. Both alloys have very good corrosion resistance. Monel 400 is magnetic in some cases, and Monel K-500 is non-magnetic in any case.

What is the melting point of Monel K500?

2400-2460° F.

What special metals are in Monel K500?

MONEL K500 is a nickel-copper alloy, precipitation hardenable through additions of aluminum and titanium. MONEL K500 retains the excellent corrosion resistant characteristics of 400 and has enhanced strength and hardness after precipitation hardening when compared with 400.

Why is Monel expensive?

Monel 400 remains expensive mainly due to its high nickel content and its use in specialized industries that constantly drive the market demand for this alloy. When you compare the price of Monel 400 with the price of stainless steel, you find that the former is much more expensive.

What is the difference between Inconel 718 and Monel K500?

While both alloys offer high levels of strength and corrosion resistance when exposed to extreme conditions, Monel K500 has better fatigue properties, while Inconel 718 has better creep resistance at higher temperatures.

Monel K500 Chemical Composition:

Composition Ni Cu Al Ti Fe Mn S C Si
Content (%) Min. 63 27.0 2.30 0.35          
  Max.   33.0 3.15 0.85 2.0 1.5 0.01 0.25 0.5

Monel K500 Mechanical Properties:

Tensile Strength (σb/MPa) Yield Strength (σp0.2/MPa) Elongation (σ5/%)
1100 790 20

 Monel K-500 Corrosion Resistant:

The corrosion resistance of alloy K-500 is substantially equivalent to that of alloy 400 except that when in the age-hardened condition, nickel alloy K-500 has a greater tendency toward stress-corrosion cracking in some environments. Monel K-500 has been found to be resistant to a sour-gas environment. The combination of very low corrosion rates in high-velocity sear water and high strength make alloy K-500 particularly suitable for shafts of centrifugal pumps in marine service. In stagnant or slow-moving sea water, fouling may occur followed by pitting but this pitting slows down after a fairly rapid initial attack.

Monek K500 Applications:

  • Sour-gas service applications
  • Oil and gas production safety lifts and valves
  • Oil-well tools and instruments like drill collars
  • Oil well industry
  • Doctor blades and scrapers
  • Chains, cables, springs, valve trim, fasteners for marine service
  • Pump shafts and impellers in marine service

Monel k500 Heat Treatment:

  • Soft material (140-180 Brinell, 75-90 RB). Hold for 16 hrs at 1100 to 1125°F followed by furnace cooling at the rate of 15 to 25°F per hr to 900°F.
  • Moderately cold-worked material (175-250 Brinell, 8-25 RB).
  • Fully cold-worked material (260-325 Brinell, 25-35 Rc).

Monel K500 Hardness:

Hardness of the specimens ranged from 28 to 40 Rc. The combination of very low corrosion rates in high-velocity sea water and high strength make alloy K-500 particularly suitable for shafts of centrifugal pumps in marine service.


Post time: Mar-25-2023