What material is Inconel 625 alloy in China?
Inconel 625 alloy introduction:
625 This alloy has excellent corrosion resistance and oxidation resistance, both has good tensile properties and fatigue properties from low temperature to high temperature 980°C, and has the ability to resist stress corrosion in salt spray atmosphere. Therefore, it can be widely used in the manufacture of aerospace engine parts, aerospace structural parts and chemical equipment, as well as in situations where it is in contact with seawater and subjected to high mechanical stress.
Inconel 625 alloy chemical composition:
Brand: Inconel 625 (UNS N06625/W.Nr.2.4856)
National standards: UNS American standard: N06625 W. Nr./EN European standard: 2.4856 ASTM: B 443, B 444, B 446, B 564, B 366 AMS: 5599, 5581, 6555, 5837 ASME: SB- 443, SB - 444, SB-446, SB-564, SB-366 NACE: MR0175-3 ISO: 15156-3
chemical composition:
Chromium Nickel Molybdenum Cobalt Niobium+Tantalum Aluminum Titanium Carbon Iron Manganese Silicon Phosphorus Sulfur
Minimum value 20.0 -- 8.0 -- 3.15 -- -- -- -- -- -- -- --
Maximum value 23.0 Margin 10.0 1.0 4.15 0.4 0.4 0.1 5.0 0.5 0.5 0.015 0.015
Inconel 625 Features:
1. It has excellent corrosion resistance against various corrosive media in oxidizing and reducing environments.
2. Excellent resistance to pitting corrosion and crevice corrosion, and will not produce stress corrosion cracking caused by chloride
3. Excellent resistance to inorganic acid corrosion, such as nitric acid, phosphoric acid, sulfuric acid, hydrochloric acid and mixed acids of sulfuric acid and hydrochloric acid, etc.
4. Excellent resistance to corrosion by various inorganic acid mixed solutions
5. When the temperature reaches 40°C, it can show good corrosion resistance in hydrochloric acid solutions of various concentrations.
6. Good processability and weldability, no post-weld cracking sensitivity
7. Manufacturing certification of pressure vessels with wall temperature between -196~450°C
8. Certified by the NACE standard of the American Society of Corrosion Engineers (MR-01-75) to meet the highest standard level VII for use in sour gas environments.
Metallographic structure: 625 has a face-centered cubic lattice structure. When kept at about 650°C for a long enough time, carbon particles and unstable quaternary phase will precipitate and be converted into a stable Ni3(Nb,Ti) orthorhombic lattice phase. After solid solution strengthening, the molybdenum and niobium components in the nickel-chromium matrix will improve the mechanical properties of the material, but the plasticity will be reduced.
Corrosion resistance: Alloy 625 has excellent corrosion resistance in many media. It has excellent resistance to pitting corrosion, crevice corrosion, intergranular corrosion and chloride medium corrosion. It has good corrosion resistance to inorganic acids such as nitric acid, phosphoric acid, sulfuric acid, hydrochloric acid, etc., and is also resistant to alkali and organic acid corrosion in oxidizing and reducing environments. Effectively resists chloride ions and reduces stress corrosion cracking. There is almost no corrosion in seawater and industrial gas environments, and it has high corrosion resistance to seawater and salt solutions even at high temperatures. No sensitivity during welding. It is resistant to carbonization and oxidation in static or cyclic environments, and is resistant to corrosion from chlorine-containing gases.
Process performance and requirements: Thermal processing
1. Thermal processing temperature range is 1150°C ~ 900°C, and the cooling method is water quenching or other rapid cooling methods.
2. In order to obtain the best performance and corrosion resistance, annealing treatment should be carried out after hot working.
3. When heating, the material can be directly fed into the furnace that has been heated to the maximum working temperature. After being kept warm for a sufficient time (60 minutes of holding time is required for each 100mm thickness), it can be quickly discharged from the furnace and thermally processed in the high temperature section of the specified temperature range. When the material temperature drops below the thermal processing temperature, it needs to be reheated.
Cold working
1. Cold worked materials should be annealed, and their work hardening rate should be greater than that of austenitic chromium-nickel stainless steel.
2. During cold working, intermediate annealing is required.
3. When the processing amount is greater than 15%, annealing treatment is required after hot processing.
Welded
1. Suitable for welding using any traditional welding process
.2. The materials to be welded should be in a solution-treated state, and oxide scale, oil stains and various markings and marks should be removed.
3. Heat treatment is no longer required before and after welding.
Application scope of Inconel 625 Application areas are: Softened and annealed low carbon alloy 625 is widely used in the chemical processing industry. Its good corrosion resistance and high strength enable its use as thinner structural components. Alloy 625 can be used where exposed to seawater and subjected to high mechanical stress.
Typical application areas: 1. Chloride-containing organic chemical process components, especially where acid chloride catalysts are used. 2. Digesters and bleaching tanks used in the pulp and paper industry. 3. Flue gas desulfurization system. Absorption tower, reheater, flue gas inlet baffle, fan (humidity), stirrer, baffle and flue, etc. 4. Used to manufacture equipment and parts for use in acidic gas environments 5. The reaction of acetic acid and acetic anhydride occurs 6. Sulfuric acid condenser.
