Alloy 625, UNS N06625, gains its strength from molybdenum and niobium in solid solution rather than from precipitation, so it arrives strong in the annealed condition and needs no aging. The high chromium and molybdenum content give outstanding resistance to pitting, crevice corrosion, chloride stress corrosion cracking and a wide range of acids.
It also holds up to about 1800F in oxidizing service, which is why it appears in both chemical process equipment and aerospace exhaust and bellows hardware.
Stocked as bar, plate, sheet, tube and forgings in Grade 1 annealed and Grade 2 solution annealed conditions.
Sizes and stock
- Round bar: up to 12" DIA
- Foil: from .0005" THK
- Sheet / plate: up to 4" THK
- Tube: various sizes
- Forgings and flat bar: by request
Processing capabilities
- Billet conversion and open die, closed die and ring forging
- Solution treat, age and anneal to the applicable spec
- Saw cutting, trepanning, gun drilling and CNC machining
- Ultrasonic, penetrant dye, micrography and physical testing
Specifications
Material is released to the applicable specification with mill test reports and, on request, independent lab verification.
Why engineers specify Inconel 625
- Outstanding corrosion resistance in seawater and acid service
- High strength in the annealed condition with no aging required
- Excellent weldability and fabricability
- Useful strength and oxidation resistance to high temperature
Nominal chemistry
Percent by weight, nominal composition per the governing specification. The mill test report for your heat is the controlling document.
Typical mechanical properties
| Condition | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|
| Annealed (Grade 1) | 120 ksi min | 60 ksi min | 30% min | - |
| Solution annealed (Grade 2) | 100 ksi min | 40 ksi min | 30% min | - |
Typical published values for reference only, not for design. Properties vary with section size, product form and processing. Order to the specification and condition your drawing requires.
Typical applications
- Seawater and subsea equipment
- Chemical process piping and vessels
- Aircraft exhaust ducting and bellows
- Flare stacks and scrubber hardware
- Downhole and sour service components
Fabrication notes
Machining
Nickel and cobalt superalloys work harden aggressively. Use rigid setups, sharp tooling, slow speeds, positive feed that stays under the hardened skin, and flood coolant. Age hardened material machines far more slowly than solution treated material, so rough before aging wherever the print allows.
Welding
Most solid solution grades weld readily with matching filler. Age hardenable grades such as 718 and Waspaloy are welded in the solution treated condition and aged afterward to control strain age cracking.
Forming
Hot working ranges are narrow and forces are high. Cold form in the annealed condition with intermediate anneals, and stress relieve before final heat treatment.
Inconel 625 compared with similar grades
Alloy 718
Much higher strength after aging, less corrosion resistant.
Hastelloy C-276 / C-22
Higher resistance to reducing acids and severe chloride attack.
Designations and cross reference
- Material family
- Nickel & Cobalt Alloys
- UNS number
- N06625
- Werkstoff (W.Nr)
- 2.4856
Working from an obsolete, foreign or superseded designation? Send it over and we will cross reference it to a current grade and specification.
Quality, testing and traceability
Supplied with mill test reports and heat traceability, with ultrasonic inspection, penetrant dye, micrography, grain size, stress rupture and mechanical testing available on request.
We are AS9100D and ISO 9001:2015 registered. If our stock does not already carry the inspection your specification requires, we can quote the material with that work performed. More on our quality system
Available forms
Inconel 625 frequently asked questions
What is Inconel 625?
Alloy 625, UNS N06625, gains its strength from molybdenum and niobium in solid solution rather than from precipitation, so it arrives strong in the annealed condition and needs no aging. The high chromium and molybdenum content give outstanding resistance to pitting, crevice corrosion, chloride stress corrosion cracking and a wide range of acids.
What forms is Inconel 625 available in?
We supply Inconel 625 in bar, foil, sheet, plate, tube, forging. Custom sizes are converted from billet, and we can provide saw cut, waterjet or near net blanks so material arrives closer to your finished part.
What is the UNS or equivalent designation for Inconel 625?
Inconel 625 is designated UNS N06625, Werkstoff 2.4856. If your drawing calls out an obsolete or foreign designation we can cross reference it and confirm the equivalent before you order.
What specifications can Inconel 625 be supplied to?
Commonly ordered specifications include AMS 5599, AMS 5666, AMS 5581, PWA 1066, PWA 1072, UNS N06625. Material is released to the specification and condition on your purchase order, with mill test reports supplied as standard.
What conditions can Inconel 625 be ordered in?
We can supply Annealed (Grade 1), Solution annealed (Grade 2). If our stock is not already in the condition you need, we can quote it with the heat treatment performed before shipment.
Can you cut Inconel 625 to size?
Yes. Saw cutting, waterjet, laser and shearing are available, along with trepanning, gun drilling, lathe turning and CNC machining, so you can order blanks or rough machined pieces rather than full lengths.
Do you provide test reports and additional testing on Inconel 625?
Every order ships with mill test reports and heat traceability. If your print calls for ultrasonic inspection, penetrant dye, magnetic particle, chemical assay, micrography, hardness or mechanical testing and our stock does not already carry it, we can quote the material with that work performed.
Can Inconel 625 be supplied to DFARS domestic melt requirements?
Tell us at quote stage if the order is DFARS or domestic melt restricted and we will confirm availability against that requirement before you commit.
What do you need to quote Inconel 625?
Grade, form, dimensions, quantity, specification and condition, plus any testing or certification requirements and the date you need it. Send a drawing if you have one. Quotes are typically ready within 24 hours.
How does Inconel 625 compare with Alloy 718?
Much higher strength after aging, less corrosion resistant.