Summary
Inconel 625 and 718 are two commonly encountered Inconel grades. They look alike and are easy to confuse by eye, but they do different jobs. 625 is a corrosion alloy that happens to be strong; 718 is a strength alloy that happens to resist corrosion. In scrap, 625 arrives mostly as pipe, plate and clad pipe from offshore and chemical plant; 718 arrives mostly as turnings and forgings from aerospace and oilfield machining.
For value, 625 carries more nickel and molybdenum; 718 carries more niobium but much more iron. Keep them separate: a buyer melting either one can’t accept the other.
Side by Side
| Inconel 625 | Inconel 718 | |
|---|---|---|
| Strengthening | Solid solution (Mo, Nb) | Precipitation (γ″, Ni₃Nb) |
| Main purpose | Corrosion resistance | High strength |
| Typical service | Offshore pipe, scrubbers, chemical plant | Jet engine discs, shafts, oilfield tools |
| Common scrap forms | Pipe, plate, clad pipe, turnings | Turnings, forgings, bar ends |
| Weld filler | ERNiCrMo-3 | ERNiFeCr-2 |
Composition Compared
Nominal compositions compared element by element. Change either grade to compare others.
On the XRF
Switch the grade to see how the fingerprint changes. See how XRF sorts nickel alloys.
FAQ
What is the main difference between Inconel 625 and Inconel 718?
Inconel 625 is a solid-solution nickel-chromium-molybdenum alloy (about 9% Mo, under 5% Fe) chosen for corrosion resistance. Inconel 718 is a precipitation-hardened alloy with about 18% iron and 5% niobium, chosen for strength up to about 650 °C (1,200 °F).
Can Inconel 625 and Inconel 718 scrap be mixed?
No. Keep them separate. A melter buying either one needs its chemistry to stay within the grade’s limits, and mixing can mean a re-sort or a different valuation.