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This post was last edited by goldliyang on 2020-12-23 at 11:01. Monel K500 (Ni68Cu28Al); MonelK-500/NO5500/2.4375. The Monel K500 alloy possesses excellent corrosion resistance, as well as higher strength and hardness compared to Monel 400. This is due to the addition of elements such as Al and Ti to the alloy; after certain heat treatment, dispersed intermetallic compounds exist within the matrix. The microstructure consists of a single-phase austenite structure with dispersed Ni3(Al, Ti) precipitates. Monel K500 has a yield strength approximately three times that of Monel 400 and a tensile strength twice that of it, and higher mechanical properties can be achieved through cold working or aging. Monel K500 alloy has the same corrosion resistance as Monel 400 alloy. Monel K500 alloy is mainly used for pump shafts and impellers, conveyor scrapers, oil well drill rings, elastic components, valve gaskets, etc. Other products include various heat exchange equipment, boiler feed water heaters, oil and chemical pipelines, containers, towers, tanks, valves, pumps, reaction vessels, shafts, and more. Due to its low corrosion rate in flowing seawater and the high strength of this alloy, Monel K500 is suitable for manufacturing centrifugal pump shafts resistant to seawater corrosion. Applicable to still and flowing seawater. Chemical composition of Monel K500 alloy: Carbon C: ≤0.25, Nickel Ni: 63–67, Aluminum Al: ≤2–4, Titanium Ti: ≤0.25–1.00, Iron Fe: ≤2.0, Manganese Mn: ≤1.5, Silicon Si: ≤1.00, Copper Cu: balance, Sulfur S: ≤0.01, Magnesium Mg: 0.08–0.12. Physical properties of Monel K500 alloy: Density: 0.318 lb/in3; 8.80 g/cm3. Elastic modulus: 26,000 ksi. Electrical resistivity: 5.11e-005 ohm-cm. Heat capacity: 0.427 J/g-°C. Thermal conductivity: 22 W/m-°C. Melting point: 1300 – 1350 °C. Magnetic susceptibility: 200 H (at 70°F). Tensile strength: 70–90 MPa. Yield strength (0.2% offset): 482–621 ksi. Common names: MONEL Alloy 400, UNS N04400, NiCu30Fe. W-Nr: 2.4360. Other names: Nicorros-Alloy 400, ATI 400, NAS NW400. Standards followed: ASTM B127/ASME SB-127, ASTM B163/ASME SB-163, ASTM B165/ASME SB-165. Major components: Carbon (C) ≤ 0.30, Nickel (Ni) ≥ 63.0, Silicon (Si) ≤ 0.5, Sulfur (S) ≤ 0.024, Iron (Fe) ≤ 2.5, Manganese (Mn) ≤ 2.0, Copper (Cu): 28.0 – 34.0. Physical properties: Density: 8.9 g/cm3; Melting point: 1300–1350 °C. Magnetic susceptibility: None. Mechanical properties: Tensile strength: σb ≥ 480 MPa; Yield strength: σb ≥ 195 MPa. Elongation: δ ≥ 35%. Hardness ； Corrosion resistance and main application environments of HB135-179: Monel400 generally has superior corrosion resistance compared to nickel-copper alloys; it is more resistant to corrosion in reducing media than pure nickel, and more resistant to corrosion in oxidizing media than pure copper. It also exhibits excellent corrosion resistance to sulfuric acid, phosphoric acid, and carbon. In particular, it resists corrosion by hydrochloric acid, and also exhibits excellent corrosion resistance to hot concentrated alkalis. The Monel400 alloy exhibits excellent corrosion resistance in fluorine gas, hydrochloric acid, sulfuric acid, hydrofluoric acid, and their derivatives. It also has better corrosion resistance in seawater than copper-based alloys. Monel400 is a deformable nickel-copper-based nickel alloy that exhibits excellent resistance to seawater corrosion and chemical corrosion, as well as strong resistance to chloride stress corrosion cracking. This alloy is one of the few alloys that can be used in fluorides. It exhibits excellent resistance to oxide stress cracking corrosion in hydrofluoric acid and fluorine gas media, such as in seawater and saline environments. In moderately concentrated alkaline and saline solutions, Monel 400 also exhibits very good corrosion resistance. In colder alkaline environments, this alloy is used in weak acids such as sulfur and hydrogen fluoride. Acidic medium: Monel400 is corrosion-resistant in sulfuric acid with concentrations below 85%. Monel400 is one of the very few important materials resistant to hydrofluoric acid. Water corrosion: In most cases of water corrosion, the Monel400 alloy exhibits excellent corrosion resistance; pitting and stress corrosion are also rare occurrences, with a corrosion rate of less than 0.025 mm/a. High-temperature corrosion: The maximum temperature at which Monel400 can operate continuously in air is generally around 600°C; in high-temperature steam, the corrosion rate is less than 0.026 mm/year. Ammonia: Due to its high nickel content, the Monel400 alloy can resist corrosion in anhydrous ammonia and under ammoniation conditions at temperatures below 585°C.