Q: What is a Monel Bolt?
A: Monel bolts are made of Nickel copper alloy known as Monel. They can also be referred to as Alloy 400 bolts or Alloy K500 bolts depending on the grade. Monel bolts come mainly in two grades Monel 400 and Monel K500. Both offer similar corrosion resistance but K500 bolts offer 2x the strength of grade 400 bolts.
As a nickel alloy, Monel is especially known for its resistance to saltwater. It is renowned for its excellent resistance to harsh seawater environments. Due to its combination of strength and saltwater corrosion resistance, it is the go-to material by the military and navy for marine environments.
In addition, Monel bolts are also excellent for cryogenic service. Even at temps below -300°F, Monel retains much of its ductility and toughness. In fact, in US Navy tear tests Monel still offers excellent mechanical properties at temps as low as -320°F.
Monel K500 is also excellent for cryogenic service. As temperatures go down, Monel K500’s tensile and yield strength increase – with little or no change to ductility and toughness. It is even usable as low as the temperature of liquid hydrogen.