Monel 400 lock nuts are the right choice for underwater applications as they are resistant to seawater at high temperatures. These lock nuts are also resistance to steam, salt, and caustic solutions and rapidly flowing brackish water.

Monel 400 is made of at least 63 percent nickel and between 29 and 34 percent copper, between 2 and 2.5 percent iron and between 1.5 and 2 percent manganese. A nickel alloy, Monel 400 is hardened by cold working.

Characteristics monel 400 locknuts                   

  • Good corrosion resistance
  • Good weldability
  • Moderate to high strength
  • Slightly magnetic at room temperature
  • Good mechanical properties from subzero temperatures up to 1000°F in oxidizing atmospheres


  • Chemical processing equipment
  • Oil industry
  • Marine industry
  • Steam generators
  • Brine heaters
  • Seawater scrubbers
  • Sulfuric acid and hydrofluoric acid alkylation plants
  • Heat exchangers
  • Oil refineries
  • Uranium and isotope separation refineries for nuclear fuel
  • Plastics plants
  • Propeller and pump shafts
  • Marine fixtures and fasteners
  • Electrical components
  • Gasoline and fresh water tanks
  • Crude petroleum stills
  • Boilers
  • Heaters
  • Offshore oil and gas drilling

We offer lock nuts in a variety of styles:

  • Grade C all-metal cone
  • Grade A reversible
  • Flexloc nut
  • Nylon insert

Products are made in the USA. Whether you need a standard or custom size, KD Fasteners has a solution for you. Contact us today by calling 1-800-736-5014 or filling out our contact form.