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Castle Metals have alloy 625 in stock and can supply in sheet, plate, and bar forms. Our added processing capabilities and quality standards means we can provide for a range of industries.
Alloy 625 (UNS N06625) is a low-carbon Ni-Cr-Nb alloy which shows excellent resistance to a variety of corrosive media.
Due to its low carbon content and stabilising heat treatment, alloy 625 shows little tendency to sensitisation even after 50 hours at temperatures in the range 650-900°C (1200-1650°F).
The alloy is supplied in the soft-annealed condition for applications involving wet corrosion, and is approved by TUV for pressure vessels in the temperature range -196-450°C (-321-840°F).
For high-temperature applications a modiﬁed version of alloy 625 is available on request.
The mechanical properties of alloy 625 can be increased by age-hardening.
This alloy is characterised by:
In special high-temperature applications where very high strength and creep values are required, the high-carbon, solution treated version (Alloy 625, grade 2) should be used.
Alloy 625 has a face-centred cubic structure. After long exposures at a temperature of about 650°C (1200°F) the alloy precipitates some isolated carbides and a metastable tetragonal phase which later changes to a stable orthorhombic phase Ni3 (Nb, Ti). The mechanical properties are enhanced by
the molybdenum and niobium content through solid-solution hardening of the nickel-chromium matrix. There is, however , a loss in ductility.
Alloy 625 shows excellent corrosion resistance in a wide range of media:
|Tube & Pipe||Sheet
|France AFNOR||NC 22 DNb|
|W.-Nr . 2.4856
|Sheet, Strip cr||830||120||415||60||30||150 – 220|
|Sheet, Plate hr||≤ 75||≤ 3||760||110||380||55|
|Rod, Bar||≤ 100||≤ 4||830||120||415||60|
The soft annealed, low carbon alloy 625 is widely used in chemical process technology, as its good corrosion resistance and high strength permit the use of thin structural parts. Alloy 625 is used for structures in contact with seawater and subject to high mechanical stresses.
For high-temperature applications, up to about 1000°C (1830°F), the solution- annealed, high carbon version (alloy 625, grade 2) is recommended, due to its excellent creep properties.