Alloy 625 is used due to its high strength and excellent corrosion resistance in aqueous media as well as in high temperature oxidizing and carburizing environments. The high chromium and molybdenum content provides a high degree of pitting and crevice corrosion resistance to chloride-containing media such as seawater, neutral salts and salt solutions. The alloy is highly resistant to chloride stress corrosion cracking due to its high nickel content. The strength of Alloy 625 is derived from the matrix-strengthening effect of molybdenum and niobium, which means hardening heat treatments are unnecessary. Alloy 625 retains its excellent ductility and toughness at cryogenic temperatures. It also has excellent malleability and is easy to weld.
Main fields of application of alloy 625
– Natural gas pipelines
– Production systems and pipe coverings of riser pipes in oil production
– Preparation of phosphoric acid
– Shipbuilding and marine water lines
– Plants for the treatment of radioactive waste
– Flue gas scrubbers and dampers in flue gas cleaning systems
Areas of application for ALLOY 625
Seals and closures, piping and exhaust systems, motorsport exhaust systems, bellows and expansion joints, furnace equipment, valve components.
Chemical composition – limits in %
| Ni | min. 58,00 |
| Cr | 20,00 – 23,00 |
| Mo | 8,00 – 10,00 |
| Fe | max. 5,00 |
| Nb | 3,15 – 4,15 |
| Mn | max. 0,50 |
| Si | max. 0,50 |
| Al | max. 0,40 |
| Ti | max. 0,40 |
| C | max. 0,10 |
Mechanical Properties
| Temper | Annealed (Grade1) | Solution-treated (Grade 2) | ||
|---|---|---|---|---|
| Tensile Rm | 120 | ksi (min) | 100 | ksi (min) |
| Tensile Rm | 827 | MPa (min) | 690 | MPa (min) |
| R.p. 0.2% Yield | 60 | ksi (min) | 40 | ksi (min) |
| R.p. 0.2% Yield | 414 | MPa (min) | 276 | MPa (min) |
| Elongation (2” or 4D gl) | 30 | % (min) | 30 | % (min) |
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