Nickel Alloy Inconel 625-O (Annealed)
Temper · default condition
UNS N06625 · ASTM B443 · EN 2.4856, NiCr22Mo9Nb · GB GH3625
Standard stocked condition for sheet, plate, bar and pipe used below ~600 °C; best combination of strength, ductility and corrosion resistance.
Values for the O condition
Other Inconel 625 tempers and conditions
Inconel 625 is listed in 10 conditions; see the grade overview at Inconel 625.
- Grade 2 Solution Treated
- Solution Annealed
- HIP
- O
- As Welded
- Hot Finished
- Stress Relieved
- As Printed
- Aged
- Cold Drawn
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Grade 2 | ASTM B443/B444 Grade 2 material solution-treated at 1093–1204 °C for elevated-temperature service, giving lower strength but greater creep resistance and ductility than the mill-annealed Grade 1. | 330 | 760 | 50 | 170 HB | 1.3 % IACS |
ASTM B443 Grade 2, 1090–1200 °C + rapid cool | Choose for service above ~600 °C where creep resistance and freedom from carbide/δ-phase embrittlement matter more than room-temperature strength. | 390 | 830 | 55 | 165 HB | — |
Hot isostatic pressed | For additive or cast parts needing near-zero porosity and isotropic, fatigue-critical properties (aerospace, subsea). | 450 | 900 | 48 | 175 HB | 1.3 % IACS |
ODefaultThis page Annealed | Standard stocked condition for sheet, plate, bar and pipe used below ~600 °C; best combination of strength, ductility and corrosion resistance. | 490 | 930 | 45 | 190 HB | — |
GTAW/GMAW deposit with ERNiCrMo-3 filler, no PWHT | Reference condition for weldments and weld overlays; strength meets base-metal annealed minima without post-weld heat treatment. | 500 | 830 | 35 | 200 HB | 1.3 % IACS |
hot rolled / hot forged, not annealed | Economical condition for heavy bar, forgings and rings that will be machined and heat treated by the customer. | 520 | 940 | 40 | 19 HRC | 1.3 % IACS |
870 °C/1 h (wrought) or 800–900 °C (AM parts) air cool | Use to remove residual stress from cold work, welding or laser powder-bed printing while keeping most of the as-worked/as-printed strength. | 680 | 960 | 35 | 30 HRC | 1.3 % IACS |
laser powder-bed fusion / DMLS, no post heat treatment | Baseline for SLM/DMLS IN625 parts; fine cellular microstructure gives high yield strength but anisotropy and high residual stress. | 720 | 990 | 35 | 30 HRC | — |
Solution annealed + precipitation aged | Pick when maximum room- and mid-temperature strength/hardness is needed (springs, fasteners, downhole tools); ductility and toughness drop. | 860 | 1,200 | 25 | 35 HRC | — |
bar, wire and tube drawn without final anneal | Choose for high-strength wire, springs, fasteners and precision tube where cold-work strengthening replaces heat treatment. | 900 | 1,100 | 20 | 32 HRC | 1.3 % IACS |
What is Inconel 625-O?
Inconel 625-O is Inconel 625 in the O temper — standard stocked condition for sheet, plate, bar and pipe used below ~600 °C; best combination of strength, ductility and corrosion resistance. Inconel 625-O has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 71% of nickel alloy grades. Elongation at break is 45% and the elastic modulus is 207.5 GPa (30.1 Msi). Inconel 625-O has a density of 8.44 g/cm³ (0.305 lb/in³), heavier than 60% of nickel alloy grades. It melts at 1,290°C (2,354 °F).
Advantages
- Readily welded — 88/100, better than 92% of nickel alloy grades
- Good corrosion resistance — 90/100, better than 85% of nickel alloy grades
Limitations
- Poor heat conductor — 9.8 W/m·K (5.66 BTU/hr·ft·°F), worse than 92% of nickel alloy grades
Inconel 625-O properties
Typical room-temperature values for Inconel 625-O; 12 are specific to this condition. Other listed values are Inconel 625 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Inconel 625-O has a density of 8.44 g/cm³ (0.305 lb/in³), heavier than 60% of nickel alloy grades. It melts at 1,290°C (2,354 °F).
Mechanical16
Inconel 625-O has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 71% of nickel alloy grades. Elongation at break is 45% and the elastic modulus is 207.5 GPa (30.1 Msi).
Thermal6
Inconel 625-O is rated for continuous service to 650°C (1,202 °F). It conducts heat at 9.8 W/m·K (5.66 BTU/hr·ft·°F), worse than 92% of nickel alloy grades. Thermal expansion is 12.8 µm/m·K (7.11 µin/in·°F).
Electrical3
Inconel 625-O conducts electricity at 1.3 % IACS, worse than 89% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 85% of nickel alloy grades.
Sustainability4
Producing a kilogram of Inconel 625-O takes about 225 MJ of energy and emits 14 kg of CO₂ — more than 87% of nickel alloy grades. Typical recycled content is 35%.
Manufacturability8
Inconel 625-O's machinability is poor (18/100, worse than 61% of nickel alloy grades); weldability excellent (88/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Inconel 625-O
Is Inconel 625 easy to machine?
Machine like a gummy austenitic superalloy: rigid setups, positive-rake carbide or ceramic tooling, 20–35 m/min with carbide, heavy constant feed to cut under the work-hardened layer, and flood high-pressure coolant.
Can Inconel 625 be welded?
Readily welded by GTAW/GMAW/PAW/laser with ERNiCrMo-3 filler, no preheat and normally no PWHT; keep interpass temperature low, use stringer beads and avoid 650–760 °C dwell to prevent sensitization and knife-line attack.
Can Inconel 625 be formed, bent or molded?
Cold forms well but needs ~2× the press capacity of 304 stainless and frequent intermediate anneals at 980–1040 °C; hot work 950–1200 °C, never in the 760–870 °C range for heavy reductions.
What surface finishes work on Inconel 625?
Pickle/descale in nitric-HF after annealing, then electropolish or mechanically polish; not anodizable — use passivation, glass-bead or electropolished finishes, and grit-blast only with alumina to avoid iron contamination.
Inconel 625 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cr | 20 – 23 | 21.5 |
| Mo | 8 – 10 | 9 |
| NbNb+Ta combined | 3.15 – 4.15 | 3.65 |
| Fe | ≤ 5 | 3 |
| Coif determined | ≤ 1 | 0.2 |
| Al | ≤ 0.4 | 0.2 |
| Ti | ≤ 0.4 | 0.2 |
| Mn | ≤ 0.5 | 0.2 |
| Si | ≤ 0.5 | 0.2 |
| C | ≤ 0.1 | 0.05 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| Nibalance, min 58 % per ASTM B443/UNS N06625 | ≥ 58 (balance) |
Inconel 625-O — frequently asked
What is Inconel 625-O used for?
Inconel 625-O is typically used for subsea piping and umbilical tubing, aerospace exhaust ducts and bellows, flue-gas desulfurization components, seawater heat exchangers, chemical process vessels and pipe spools and downhole safety valve components. In short: marine corrosion superalloy.
What is the yield strength of Inconel 625-O?
Inconel 625-O has a typical yield strength of 490 MPa (71.1 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 71% of nickel alloy grades. Strength varies by condition: see the 10 listed tempers.
Is Inconel 625-O easy to machine?
Not especially — machinability is rated poor (18/100, worse than 61% of nickel alloy grades). Machine like a gummy austenitic superalloy: rigid setups, positive-rake carbide or ceramic tooling, 20–35 m/min with carbide, heavy constant feed to cut under the work-hardened layer, and flood high-pressure coolant.
Can Inconel 625-O be welded?
Yes — weldability is rated excellent (88/100). Readily welded by GTAW/GMAW/PAW/laser with ERNiCrMo-3 filler, no preheat and normally no PWHT; keep interpass temperature low, use stringer beads and avoid 650–760 °C dwell to prevent sensitization and knife-line attack.
What surface finishes work on Inconel 625-O?
Pickle/descale in nitric-HF after annealing, then electropolish or mechanically polish; not anodizable — use passivation, glass-bead or electropolished finishes, and grit-blast only with alumina to avoid iron contamination.
Can Inconel 625-O be formed, bent or molded?
Cold forms well but needs ~2× the press capacity of 304 stainless and frequent intermediate anneals at 980–1040 °C; hot work 950–1200 °C, never in the 760–870 °C range for heavy reductions.
What is the maximum service temperature of Inconel 625-O?
Inconel 625-O is rated for continuous use to about 650°C (1,202 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Inconel 625-O and Inconel 625 Aged?
O is the default condition — standard stocked condition for sheet, plate, bar and pipe used below ~600 °C; best combination of strength, ductility and corrosion resistance. Aged: pick when maximum room- and mid-temperature strength/hardness is needed (springs, fasteners, downhole tools); ductility and toughness drop. Yield strength is 490 MPa in O versus 860 MPa in Aged.
Can FabDigit make parts in Inconel 625-O?
Yes — Inconel 625-O is available for CNC machining, sheet metal and 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B443 / B444 / B446 — Alloy N06625 plate, sheet, strip, pipe and bar — ASTM International (2019)
- GB/T 15007 / GB/T 15062 — (GH3625/NS3306 ) — SAC (2017)
- INCONEL alloy 625 Publication SMC-063 — Special Metals Corporation (PCC) (2013)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys (Ni-base superalloys) — ASM International (1990)
- MMPDS-2023 — Metallic Materials Properties Development and Standardization — Battelle/FAA (2023)
- EOS NickelAlloy IN625 material data sheet (LPBF) — EOS GmbH (2022)
- AWS A5.14 ERNiCrMo-3 filler metal specification — American Welding Society (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.