Monel400 is a corrosion-resistant alloy with the largest amount, the most widely used and excellent comprehensive properties. This alloy has excellent corrosion resistance in hydrofluoric acid and fluorine gas medium, and also has excellent corrosion resistance in hot concentrated alkali solution. At the same time, it is also resistant to corrosion by neutral solutions, water, seawater, atmosphere, organic compounds, etc. An important feature of this alloy is that it generally does not produce stress corrosion cracking and has good machinability.
The chemical composition of Monel400 alloy is mainly composed of 30%Cu and 65%Ni with a small amount of Fe (1%-2%). Due to the difference in chemical composition, it can have a variety of compounds, but there is no significant difference in corrosion resistance between them. Monel400 alloy is more resistant to corrosion by reducing media than pure nickel, and more resistant to corrosion by oxidative media than pure copper.
National standards and common names: MONEL400, ASTM B127, ASME SB-127, AMS 4554, JIS NW4400
United States UNS: N04400,
German DIN: NiCu30Fe W-Nr: 2.4360
China GB/T : NCu-28-1.5-1.8
UK BS: NA 12
Chemical composition label: Ni68Cu28Fe
Chemical element composition of Monel400 alloy: C: ≤0.3 , Si: ≤0.50, Mn: ≤2.0, Ni: ≥63, Cu: 28～34 , S: ≤ 0.024 , Fe ≤ 2.5 , unit: %
The chemical composition of Monel400 alloy is mainly composed of 30% Cu and 65% Ni with a small amount of Fe (1%-2%). The microstructure is a typical single-phase austenite structure. Since nickel and copper are mutually soluble in any proportion, there is generally no intermetallic phase precipitation. The microstructure of this alloy is observed under non-etching conditions under a metallographic microscope, and it can be seen that there are very dispersed non-metallic inclusions, such as sulfides and silicates, on the austenite matrix. Carbides may also be observed under certain conditions.
Performance
Tensile strength: σb≥450Mpa
Yield strength: σb≥170Mpa
Elongation: δ≥30%
Mechanical properties of Monel400 alloy products in various states | |||||
Material and State | Tensile Strength/Mpa | Yield Strength/Mpa | Elongation % | Hardness | |
HB | HRB | ||||
Bar: Annealed | 516～620 | 170～345 | 60～35 | 110～149 | 60～80 |
Hot working state (≤54mm profile) | 551～757 | 275～690 | 60～30 | 140～241 | 75～100 |
Hot working state (≥ 54mm profile) | 516～689 | 205～380 | 50～30 | 130～184 | 72～90 |
Cold drawn condition, after stress relief treatment | 578～827 | 380～690 | 40～22 | 160～225 | 85～20HRC |
Plate: hot rolled | 516～655 | 380～390 | 45～30 | 125～215 | 70～96 |
hot rolled and annealed | 482～585 | 195～345 | 50～35 | 110～140 | 60～76 |
Sheet: Annealed | 482～585 | 170～310 | 50～35 | ||
cold rolled, hard | 689～964 | 620～755 | 15～2 | ||
Cold Rolled Strip: Annealed | 517～585 | 170～310 | 50～35 | ||
tempered state | 689～964 | 620～895 | 15～2 | ||
Tube: cold drawn + annealed | 516～585 | 170～310 | 50～35 | ||
(seamless): cold drawn + stress relieved state | 585～827 | 380～690 | 35～15 | ||
Corrosion resistance
The corrosion resistance of Monel is generally better than that of nickel and copper. It is more resistant to corrosion by reducing media than pure nickel, and is more resistant to corrosion by oxidative media than pure copper. It has very good corrosion resistance to sulfuric acid, phosphoric acid and carbon. In particular, it is resistant to corrosion by hydrochloric acid, and also has excellent corrosion resistance to hot concentrated alkali. Monel400 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 than copper-based alloys in seawater
Monel400 is a deformable nickel-copper-based nickel-based alloy with good seawater corrosion resistance and chemical corrosion resistance, as well as chloride stress corrosion cracking resistance. This alloy is one of the few alloys that can be used in fluoride. It has good resistance to oxide stress fission corrosion in hydrofluoric acid and fluorine gas media, such as seawater and saltwater environments.
Monel 400 also has very good corrosion resistance in moderately concentrated alkaline and salt solutions.
In cooler alkaline environments, the alloy is used in weak acids such as sulfur and hydrogen fluoride.
Acid medium: Monel400 is corrosion resistant in sulfuric acid with a concentration of less than 85%. Monel400 is one of the few important materials that can resist hydrofluoric acid.
Water corrosion: In most water corrosion cases, Monel400 alloy not only has good corrosion resistance, but also pitting corrosion and stress corrosion are rarely found, and the corrosion rate is less than 0.025mm/a.
High temperature corrosion: The maximum temperature of Monel400 working continuously 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 Monel400 alloy, it is resistant to corrosion under anhydrous ammonia and ammoniated conditions below 585°C.
Matching welding consumables
Monel Monel400 electrode (ENiCu-7), Monel400 welding wire (ERNiCu-7)
USE
Marine heat exchangers, desalination equipment, salt production equipment, marine and chemical processing equipment, propeller shafts and pumps, gasoline and water tanks, etc.