Monel 400
Material grade: Monel 400 (Monel) alloy
US grade: UNS N04400
German grade: 2.4360
1.Overview of Monel 400 (N04400) Monel alloy:
Monel 400 (N04400) Monel alloy is the most widely used and has excellent overall performance in corrosion resistance.Alloy. This alloy has excellent corrosion resistance in hydrofluoric acid and fluorine gas media, and also has good corrosion resistance to hot concentrated alkaline solutions. It is also resistant to corrosion from neutral solutions, water, seawater, atmosphere, organic compounds, etc. An important feature of this alloy is that it generally does not produce stress corrosion cracks and has good machinability.
The chemical composition of Monel 400 alloy mainly consists of 30% Cu and 65% Ni with a small amount of Fe (1%-2%). The microstructure is a typical single-phase austenitic structure. Since nickel and copper can dissolve in any proportion, there is generally no intermetallic phase precipitation. Under non-etching conditions observed under a metallographic microscope, very dispersed non-metallic inclusions, such as sulfides and silicates, can be seen on the austenitic matrix. Under certain conditions, carbides may also be observed. Due to differences in chemical composition, it can have various alloy grades, but there is no significant difference in corrosion resistance among them. Monel 400 alloy is more resistant to corrosion in reducing media than pure nickel, and more resistant to corrosion in oxidizing media than pure copper.
2.Overview of Monel 400 (N04400) Monel alloy: See Table-1:
Table-1                                                        

3.Mechanical properties of Monel 400 (N04400) Monel alloy:
1. The tensile strength of Monel 400 (N04400) Monel alloy: σb≥450Mpa.
2. The yield strength of Monel 400 (N04400) Monel alloy: σb≥170Mpa.
3. The elongation of Monel 400 (N04400) Monel alloy: δ≥30%.
4.Corrosion resistance of Monel 400 (N04400) Monel alloy:
1. The corrosion resistance of Monel is generally superior to that of nickel-copper. It is more resistant to corrosion in reducing media than pure nickel, and more resistant to corrosion in oxidizing media than pure copper, with very good corrosion resistance to sulfuric acid, phosphoric acid, and carbon. In particular, it has excellent resistance to hydrochloric acid corrosion and also has good resistance to hot concentrated alkaline solutions. Monel 400 alloy has excellent corrosion resistance in fluorine gas, hydrochloric acid, sulfuric acid, hydrofluoric acid, and their derivatives.
At the same time, it is more corrosion-resistant in seawater than copper-based alloys. Monel 400 is a nickel-copper-based alloy that can be deformed and has good resistance to seawater corrosion and chemical corrosion, with strong resistance to chloride stress corrosion cracking. This alloy is one of the few alloys that can be used in fluorides. It has good resistance to oxidative stress cracking corrosion in hydrofluoric acid and fluorine gas media, such as seawater and saltwater environments. In moderately concentrated alkaline and salt solutions, Monel 400 also has very good corrosion resistance. In colder alkaline environments, this alloy is used in weak acids such as sulfur and hydrofluoric acid.
2. Acid media: Monel 400 is corrosion-resistant in sulfuric acid with a concentration of less than 85%. Monel 400 is one of the very few important materials that can withstand hydrofluoric acid.
3. Water corrosion: Monel 400 alloy has excellent corrosion resistance in most water corrosion situations, and pitting and stress corrosion are rarely found, with a corrosion rate of less than 0.025mm/a.
4. High-temperature corrosion: The maximum continuous working temperature of Monel 400 in air is generally around 600℃, and in high-temperature steam, the corrosion rate is less than 0.026mm/a. Ammonia: Due to the high nickel content of Monel 400 alloy, it can withstand corrosion under anhydrous ammonia and ammonia conditions below 585℃.
5. Welding materials for Monel 400 (N04400) Monel alloy:
Monel 400 welding rod (ENiCu-7), Monel 400 welding wire (ERNiCu-7)
6.Application fields of Monel 400 (N04400) Monel alloy:
Marine heat exchangers, seawater desalination equipment, salt production equipment, marine and chemical processing equipment, propeller shafts and pumps, gasoline and water tanks, etc.
7.Varieties, specifications, and supply status of Monel 400 (N04400) Monel alloy:
1. Variety classification: Monel400 seamless pipe, Monel400 steel plate, Monel400 round steel, Monel400 forgings, Monel400 flanges, Monel400 rings, Monel400 welded pipes, Monel400 steel strips, Monel400 wire and matching welding materials.
2. Delivery status: Seamless pipe: solution + acid white, length can be customized; plate: solution, acid pickling, edge cutting; welded pipe: solution acid white + RT% flaw detection, forgings: annealed + turned; bars in forged and rolled state, surface polished or turned; strips delivered in cold-rolled, solution soft state, deoxidized; wire delivered in solution acid pickled coil or straight bar, solution straight bar fine polished state.