Nickel Alloy K500

MONEL® alloy K-500 (UNS N05500/ W.Nr. 2.4375) is a nickel-copper alloy that combines the excellent corrosion resistance of MONEL alloy 400 with the added advantages of greater strength and hardness. The increased properties are obtained by adding aluminum and titanium to the nickel-copper base, and by heating under controlled conditions, so that submicroscopic particles of Ni3 (Ti, Al) are precipitated throughout the matrix. The thermal processing used to effect precipitation is commonly called age hardening or aging. The composition of the alloy is given in Table 1. Typical applications for MONEL alloy K-500 products are chains and cables, fasteners and springs for marine service; pump and valve components for chemical processing; doctor blades and scrapers for pulp processing in paper production; oil well drill collars and instruments, pump shafts and impellers, non-magnetic housings, safety lifts and valves for oil and gas production; and sensors and other electronic components

Nickel Alloy K500

Chemical Composition Limits
Weight% Ni+Co C Mn Fe S Si Cu Al Ti
K500 63 min 0.25 max 1.5 max 2 max 0.01 max 0.5 max 27 – 33 2.3 – 3.15 0.35 – 0.85

Typical Mechanical Properties

Material Form and Condition Tensile Strength MPa Yield Strength (0.2% Offset) MPa Elongation (%) Hardness Rockwell B
Alloy K 500 Rod and Bar Cold Drawn Annealed 621-758 276-414 50-25 75-90B
Alloy K-500 Rod and Bar Cold- Drawn Annealed and Aged 896-1310 586-827 30-20 24-35C

CORROSION RESISTANCE

The corrosion resistance of MONEL alloy K-500 is substantially equivalent to that of alloy 400 except that, when in the age-hardened condition, alloy K-500 has a greater tendency toward stress-corrosion cracking in some environments. MONEL alloy K-500 has been found to be resistant to a sour-gas environment. After 6 days of continuous immersion in saturated (3500 ppm) hydrogen sulfide solutions at acidic and basic pHs (ranging from 1.0 to 11.0), U-bend specimens of age-hardened sheets showed no cracking. The hardness of the specimens ranged from 28 to 40 Rc. The combination of very low corrosion rates in high-velocity seawater 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.

AVAILABLE PRODUCTS AND SPECIFICATIONS

MONEL alloy K-500 is designated as UNS N05500 and Werkstoff Nr. 2.4375. It is listed in NACE MR-01-75 for oil and gas service. Alloy K-500 is furnished in a wide range of standard mill forms including pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire. Popular forms and sizes are available from stock; many specialty products may be obtained from converters.

Plate, Sheet, and Strip – BS3072NA18 (Sheet and Plate), BS3073NA18 (Strip), QQ-N-286 (Plate, Sheet and Strip), DIN 17750 (Plate, Sheet and Strip), ISO 6208 (Plate, Sheet and Strip)

Bar, Rod, Wire, and Forgings – BS3075NA18 (Wire), BS3076NA18 (Rod and Bar), ASTM B 865 (Rod and Bar), DIN 17752 (Rod and Bar), DIN 17753 (Wire), DIN 17754 (Forgings), QQ-N-286 (Rod, Bar, Wire, and Forgings), SAE AMS 4676 (Rod and Bar), ASME Code Case 1192 (Rod and Bar), ISO 9723 (Bar), ISO 9724 (Wire), ISO 9725 (Forgings)

Pipe and Tube – BS3074NA18 (Seamless Pipe and Tube), DIN 17751 (Pipe and Tube)

Other Products – DIN 17743 (Chemical Composition), SAE AMS 4676 (Chemical Composition), QQ-N-286 (Chemical Composition)

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