Materials / Superalloy
Inconel 625
- UNS
- N06625
- W.Nr
- 2.4856
- EN
- NiCr22Mo9Nb
A niobium-stabilised nickel-chromium-molybdenum alloy that gets its strength from solid-solution hardening rather than heat treatment, so it arrives strong and stays strong without post-weld ageing.
Composition
| Element | Min | Max |
|---|---|---|
| Ni | 58.0 | — |
| Cr | 20.0 | 23.0 |
| Mo | 8.0 | 10.0 |
| Nb+Ta | 3.15 | 4.15 |
| Fe | — | 5.0 |
| Co | — | 1.0 |
| Al | — | 0.40 |
| Ti | — | 0.40 |
| C | — | 0.10 |
| S | — | 0.015 |
Per cent by weight, to the governing standard.
- Ni65.8
- Cr21.5
- Mo9.0
- Nb+Ta3.7
Per cent by weight, at the midpoint of each specified window. Elements given only as a maximum have no midpoint to take, so they sit inside the balance rather than being estimated; trace elements below 0.5 % are not shown. Indicative only; the composition table above and the governing standard are what define the limits.
Mechanical
- Tensile strength, min
- 827 MPa
- Yield strength (0.2%), min
- 414 MPa
- Elongation, min
- 30 %
- Condition
- Annealed
Standards by form
| Plate, sheet & strip | ASTM B443 | |
|---|---|---|
| Pipe & tube | ASTM B444 | |
| Bar & rod | ASTM B446 | |
| Fittings | ASTM B366 | |
| Forgings | ASTM B564 |
Where it is specified
- Resists pitting, crevice corrosion and chloride stress-corrosion cracking
- Seawater and sour service, flue gas desulphurisation, chemical processing
- Serviceable from cryogenic temperatures to roughly 980 °C
Niobium and molybdenum are the cost, so they are the thinning risk
Niobium and molybdenum are the two most expensive elements in the alloy, so a price cut has to come out of one of them. Material light on Nb+Ta will still look like 625 on a certificate and still weld, and it will fail in service years early.
What we specify and check
- PMI specified on the delivered heat, reading Nb+Ta and Mo against B443 limits
- Certificate cross-checked to the heat number actually in the crate
- EN 10204 3.1 or 3.2 as specified
- Intergranular corrosion testing where the service calls for it
We commission an accredited independent laboratory to test the heat before the material leaves China. You will receive that report unedited, whether it passes or not.
Request Inconel 625
Tell us the form, dimensions and service conditions. We reply with availability, indicative landed price, lead time and the test regime we would specify for your application.
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