Monel 400 Bar- Highly useful for marine environments

Monel 400 Bar is an alloy of Nickel & Copper that is resistant to sea water, salt, caustic solutions and steam at high temperatures. It has excellent corrosion resistance in a wide variety of media. It has excellent general corrosion resistance, weldability and high strength. It is resistant to rapidly flowing brackish water or seawater and is particularly resistant to hydrochloric & hydrofluoric acids when these are de-aerated. This alloy is slightly magnetic at room temperature and is widely used in chemical, oil and marine industries.

Main features of Monel400 Bar are

·        It has higher resistance under reducing conditions than Nickel and has higher resistance than copper under oxidizing conditions. It shows better resistance to reducing media than oxidizing.

·        It has corrosion resistance in an extensive range of marine & chemical environments such as pure water, salts, non-oxidizing mineral acids & alkalis.

·        It has excellent resistance to Sulfuric & Hydrofluoric acids. Aeration results in increased corrosion rates. It might handle Hydrochloric acid but the presence of oxidizing salts accelerates corrosive attack.

·        High resistance to chloride ion stress corrosion cracking.

·        Excellent mechanical properties from subzero temperatures up to about 480°C.

·        It has high resistance to alkaline, neutral and acid salts but poor resistance with oxidizing acid salts such as Ferric Chloride.

Monel 400 Bar has applications in

·        Brine heaters & sea water scrubbers in tanker inert gas systems

·        Pumps and valves used in the manufacture of perchlorethylene & chlorinated plastics.

·        Feed water and steam generator tubing.

·        Monoethanolamine (MEA) reboiling tube.

·        Sulfuric acid and hydrofluoric acid alkylation plants.

·        Plant for the refining of uranium and isotope separation in the production of nuclear fuel.

·        Pickling bat heating coils.

·        Cladding for the upper areas of oil refinery crude columns.

·        Heat exchangers in a variety of industries.

·        Propeller and pump shafts.

·        Transfer piping from oil refinery crude columns.

Anneal cycle of Monel400 Bar ranges from 1400 to 1800°C (760 to 980°C) and Annealing is performed in a sulfur compound-free atmosphere as sulfur embrittles material at the annealed temperature range. A high percentage of Monel400 is used without final heat treatment for increasing the strength of the material. Welding methods are similar to those used for austenitic stainless steels however material must be free of scaling for best weld. Preheating and post weld treatment are not required however cleaning of joint area is necessary to avoid embrittlement from paints and lubrication.

Monel 400 alloy is easily cold-shaped however it has a higher work-hardening than carbon steel. It can be considered during design & selection of forming tools & equipment and during the planning of forming processes. Intermediate annealing is essential during cold working and the strength of Monel400 alloy can be increased by hardening. Stress relief annealing is recommended in these cases especially when used in media that can cause stress corrosion cracking in nickel-copper alloys such as mercury and its compounds of fluoro-silicic acid.