Special nickel alloy Monel K500 UNS N05500 2.4375 full thread hex bolt ASME B18.2.1
Monel K500, UNS N05500 (QQ-N-286), is a precipitation-hardenable nickel-copper alloy that combines the corrosion resistance of Monel alloy 400 with greater strength (over 2x as strong) and hardness. It also has low permeability and is nonmagnetic to temperatures as low as -150¡ãF (-101¡ãC).
Monel 500 is an age-hardened version of Monel 400. This means that Monel 500 is harder and more corrosion resistant than Monel 400. Monel 500 is ideal for marine applications, where the cap screws will be integrated with salt water on a consistent basis. On the other hand, Monel 400 has high strength and toughness over a wide temperature range and is resistant to many corrosive environments but is not used in as highly of corrosive environments as Monel 500. However, Monel 400 is still ultra-strong and one of the best specialty nickel copper alloys in existence.