Monel® K-500 / N05500

Other common names: Alloy K500

Monel K500 is a Nickel-Copper alloy that is precipitation hardenable, due to the additions of Aluminium and Titanium. It combines the corrosion resistance of Monel 400 but gives the added advantage of extra strength and hardness (as a result of its age hardening ability).

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.

Relevant Standards

Monel K500 is covered by the following standards:

• BS 3075
• 3076 NA 18

Equivalent Materials

Equivalent materials to Monel K500 are:

• W.NR 2.4375
• UNS N05500
• AWS 041

   

Specifications

In what forms is Monel K500 Available at SAGAR STEELS?

• Bar
• Rod

Corrosion Resistant Monel K-500

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.

What are the characteristics of Monel K500?

• Corrosion resistance in an extensive range of marine and chemical environments. From pure water to non-oxidizing mineral acids, salts and alkalis.
• Excellent resistance to high velocity sea water
• Resistant to a sour-gas environment
• Excellent mechanical properties from sub-zero temperatures up to about 480C
• Non-magnetic alloy

   

Chemical Composition of Monel K500

The compositional range for Monel K500 is provided in the table below.

Element	Content
Ni	63 % min
Cu	30 %
Fe	2 % max
Al	2.3 - 3.15 % max
Ti	0.35 - 0.85 % max

   

Fabrication with Monel K-500

Monel K-500 is readily fabricated by standard commercial procedures.

Welding alloy K-500 is best accomplished by the gas-tungsten-arc welding process. It is recommended that Monel K-500 be annealed when it is welded and that any weldments be stress relieved prior to aging.

Heavy machining of this alloy is best accomplished when the material is in the annealed condition or hot-worked and quenched condition. Age-hardened material however can be finish-machined to close tolerances and fine finishes. Therefore, the recommended practice is to machine slightly oversize, age-harden, then finish to size. During aging, a slight permanent contraction takes place, but little warpage occurs because of the low temperatures and slow cooling rates involved.

Mechanical Properties
Typical Room Temperature Tensile Properties of Annealed Material

   

Applications of Monel K500

Monel K500 typically finds application in:

• Pump Shafts
• Fasteners
• Marine Propeller Shafts
• Oil Well Tools
• Instruments
• Springs

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