Overview
Inconel 625 is an alloy grade with density at 8.4 g/cm3 and melting point at 1290-1350 ℃. It features excellent resistance to inorganic acid corrosion and various corrosive media under oxidation and reduction environment. Alloy 625 exhibits excellent corrosion resistance in many media. For example, in chloride media, alloy 625 performs excellent resistance to pitting corrosion, crevice corrosion, intergranular corrosion and erosion.
Inconel 625 Features
625 alloy has the following features:
- 1) Excellent corrosion resistance to various corrosive media in oxidation and reduction environments;
- 2) Excellent resistance to pitting corrosion and crevice corrosion, free from 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;
- 4) Excellent corrosion resistance to mixed solution of any inorganic acid;
- 5) Good corrosion resistance in hydrochloric acid solution of various concentrations under temperature of 40℃;
- 6) Good workability and weldability, free from post-weld cracking sensitivity;
- 7) Manufacturing certification of pressure vessels with wall temperature ranging from-196℃ to 450℃;
- 8) Meeting the highest standard Grade VII for use in acidic gas environments as NACE certified(MR-01-75)
Metallographic Structure of Inconel 625
Inconel 625 has the face-centered-cubic structure. When it is exposed to 650 ℃ for heat preservation for a time long enough, the carbon particles and the unstable quaternary phase will be precipitated and transformed into a stable Ni3 (Nb, Ti) orthorhombic structure. After solid solution the molybdenum and niobium components in the Ni-Cr matrix will improve the metal mechanical properties but reduce steel plasticity.
Corrosion Resistance Performance of Inconel 625
Inconel 625 performs excellent corrosion resistance in many media. It exhibits excellent resistance to pitting corrosion, crevice corrosion, intergranular corrosion and erosion in chloride media. It has good resistance to inorganic acid corrosion, such as nitric acid, phosphoric acid, sulfuric acid, hydrochloric and etc. Meanwhile it is corrosion resistant to alkali and organic acid under the oxidation and reduction environment.
Inconel 625 also has effective stress corrosion cracking resistance (SCCR) to chlorine ion reduction. It is almost free from corrosion in seawater and industrial gases with high corrosion resistance to seawater and salt solutions even at high temperatures.
Alloy 625 shows NO sensitivity during welding process. It is resistant to carbonation and oxidation in both static and cyclic environment. It is also corrosion resistant to chlorine-containing gases.
Chemical Compositions
| Nickel | Chromium | Iron | Molybdenum | Niobium (plus Tantalum) | Carbon | Manganese | Silicon | Phosphorus | Sulfur | Aluminum | Titanium | Cobalta |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 58.0 min. | 20.0-23.0 | 5.0 max. | 8.0-10.0 | 3.15-4.15 | 0.10 max. | 0.50 max. | 0.50 max. | 0.015 max. | 0.015 max. | 0.40 max. | 0.40 max. | 1.0 max. |
Mechanical Properties
| Form and Condition | Tensile Strength | Yield Strength (0.2% Offset) |
Elongation | Reduction Of Area | Hardness, Brinell | ||
|---|---|---|---|---|---|---|---|
| ksi | MPa | ksi | MPa | % | % | ||
| ROD, BAR, PLATE | |||||||
| As-Rolled | 120-160 | 827-1103 | 60-110 | 414-758 | 60-30 | 60-40 | 175-240 |
| Annealed | 120-150 | 827-1034 | 60-95 | 414-655 | 60-30 | 60-40 | 145-220 |
| Solution-Treated | 105-130 | 724-896 | 42-60 | 290-414 | 65-40 | 90-60 | 116-194 |
| SHEET and STRIP | |||||||
| Annealed | 120-150 | 827-1034 | 60-90 | 414-621 | 55-30 | - | 145-240 |
| TUBE and PIPE, COLD-DRAWN | |||||||
| Annealed | 120-140 | 827-965 | 60-75 | 414-517 | 55-30 | - | - |
| Solution-Treated | 100-120 | 689-827 | 40-60 | 276-414 | 60-40 | - | - |
Applications of Inconel 625
The low-carbon alloy 625 (after softening annealing) is widely applied to chemical process industry. The good corrosion resistance and high strength allow it to be used as a thin structural component. 625 alloy can be used in applications which require both contacting with seawater and subjection to high mechanical stresses.
Typical application are as follows:
- 1) Components of chloride-containing organic chemical processes, especially where acidic chloride catalysts are used;
- 2) Digester and bleaching tanks for the manufacture of pulp and paper industries;
- 3) Absorption tower, re-heater, flue gas inlet baffle, fan (damp), stirrer, deflector plate and flues in the flue gas desulfurization system
- 4) Equipment and components used in acidic gas environments
- 5) Acetic acid and ethyl anhydride reaction generator
- 6) Sulfuric acid condenser
Contact Us
AEETHER CO., LIMITED produce cost-effective Inconel 625 products. If you have any requirements, you can send inquiry to our E-mail:
