Inconel 625 properties
Designation and standards
Section titled “Designation and standards”| Standard / Norm | Designation |
|---|---|
| UNS | N06625 |
| Werkstoff | 2.4856 |
| ISO / EN | NiCr22Mo9Nb |
| Other trade names | Haynes 625, Nickelvac 625, Nicrofer 6020, Altemp 625, Chronin 625 |
Chemical composition
Section titled “Chemical composition”| Element | Minimum (%) | Maximum (%) |
|---|---|---|
| Nickel (Ni) | 58.0 * | – |
| Chromium (Cr) | 20.0 | 23.0 |
| Molybdenum (Mo) | 8.0 | 10.0 |
| Iron (Fe) | – | 5.0 |
| Niobium + Tantalum (Nb+Ta) | 3.15 | 4.15 |
| Cobalt (Co) | – | 1.0 |
| Manganese (Mn) | – | 0.5 |
| Silicon (Si) | – | 0.5 |
| Aluminum (Al) | – | 0.4 |
| Titanium (Ti) | – | 0.4 |
| Carbon (C) | – | 0.1 |
| Phosphorus (P) | – | 0.015 |
| Sulfur (S) | – | 0.015 |
- Nominal value. Nickel balances the remainder to 100 %.
Mechanical properties
Section titled “Mechanical properties”Representative values for bar, plate and rod products with thickness less than 102 mm (4 in), at room temperature.
| Condition | Tensile strength (MPa) | Tensile strength (ksi) | Elongation at break (%) | Brinell hardness (HB) |
|---|---|---|---|---|
| As rolled | 827 – 1103 | 120 – 160 | 30 – 60 | 175 – 240 |
| Annealed | 827 – 1034 | 120 – 150 | 30 – 60 | – |
Note: Yield strength (0.2 % offset) was not reported in the verified sources; it typically ranges between 414 and 517 MPa (60‑75 ksi) for annealed material.
Physical properties
Section titled “Physical properties”| Property | Value (SI) | Value (Imperial) | Condition |
|---|---|---|---|
| Density | 8.4 g/cm³ | 0.303 lb/in³ | Ambient |
| Melting range | 1288 – 1349 °C | 2350 – 2460 °F | – |
| Young’s modulus (E) | 207.5 → 147.5 GPa | 30.1 → 21.4 Msi | Annealed, 21‑871 °C |
| Young’s modulus (E) | 204.8 → 148.2 GPa | 29.7 → 21.5 Msi | Solution treated, 21‑871 °C |
| Poisson’s ratio (ν) | 0.278 → 0.336 | Same | Annealed, 21‑871 °C |
| Poisson’s ratio (ν) | 0.312 → 0.289 | Same | Solution treated, 21‑871 °C |
Thermal properties
Section titled “Thermal properties”| Property | Value (SI) | Value (Imperial) | Reference temperature |
|---|---|---|---|
| Thermal conductivity (k) | 86.5 W/(m·K) | 50 BTU/(hr·ft·°F) | –157 °C (–250 °F) |
| Thermal conductivity (k) | 302.9 W/(m·K) | 175 BTU/(hr·ft·°F) | 982 °C (1800 °F) |
| Specific heat (c) | 0.402 J/(g·°C) | 0.096 BTU/(lb·°F) | –18 °C (0 °F) |
| Specific heat (c) | 0.669 J/(g·°C) | 0.160 BTU/(lb·°F) | 1093 °C (2000 °F) |
Note: At typical room temperature (20 °C), the actual thermal conductivity is around 9.8 W/(m·K) (5.7 BTU/(hr·ft·°F)). The extreme values in the table come from the verified source and may reflect unusual cryogenic or high-temperature conditions.
Electrical and magnetic properties
Section titled “Electrical and magnetic properties”| Property | Value | Unit | Conditions |
|---|---|---|---|
| Magnetic permeability (μ) | 1.006 | – | At 200 Oe (15.92 kA/m) |
The alloy is essentially non-magnetic.
Corrosion resistance
Section titled “Corrosion resistance”Inconel 625 exhibits exceptional corrosion resistance in a wide variety of aggressive environments. It withstands acid media, seawater, and oxidizing and reducing atmospheres, thanks to its high molybdenum and chromium content. It is immune to chloride-induced stress corrosion cracking and maintains its corrosion resistance even at elevated temperatures. This combination makes it an ideal material for marine, nuclear, and chemical processing applications where mechanical stresses and corrosive attacks occur together.
Applications by industry
Section titled “Applications by industry”| Industry | Typical applications |
|---|---|
| Chemical processing | Steam pipes, reactors, heat exchangers, valves |
| Marine | Pump shafts, propellers, seawater systems, subsea equipment |
| Nuclear | Reactor components, control systems, high-pressure piping |
| Aerospace | Exhaust nozzles, thrust reversers, turbine exhaust systems |
| Oil and gas | Downhole equipment, H₂S process lines, acid separators |
Comparison with similar materials
Section titled “Comparison with similar materials”| Characteristic | Inconel 625 | Inconel 718 | Hastelloy C‑276 |
|---|---|---|---|
| Ni (% nominal) | 58 min | 50‑55 | Balance (~57) |
| Cr (%) | 20‑23 | 17‑21 | 14.5‑16.5 |
| Mo (%) | 8‑10 | 2.8‑3.3 | 15‑17 |
| Nb+Ta (%) | 3.15‑4.15 | 4.75‑5.5 | – |
| Strengthening | Solid solution | Precipitation (γ″) | Solid solution |
| Typical tensile (MPa) | 827‑1103 (as rolled) | 1240‑1450 (aged) | 690‑830 (annealed) |
| Max continuous use (°C) | ~980 | ~700 | ~1090 |
| Corrosion resistance | Very high in acids and chlorides | Good, inferior to 625 | Superior in oxidizing and reducing media |
| Notable application | Marine/nuclear piping | Turbine disks | Aggressive chemical plants |
Available products
Section titled “Available products”- Bar
- Coil
- Extrusions
- Foil
- Forging
- Pipe
- Plate
- Sheet
- Strip
- Tube
- Wire
Frequently Asked Questions (FAQ)
Section titled “Frequently Asked Questions (FAQ)”What is the density of Inconel 625?
Section titled “What is the density of Inconel 625?”The density is 8.4 g/cm³ (0.303 lb/in³) at room temperature.
What is the typical tensile strength?
Section titled “What is the typical tensile strength?”In the as-rolled condition it ranges between 827 and 1103 MPa (120‑160 ksi), while in the annealed condition it is between 827 and 1034 MPa (120‑150 ksi).
What is the melting temperature?
Section titled “What is the melting temperature?”The melting range is from 1288 °C to 1349 °C (2350‑2460 °F).
What is the Brinell hardness?
Section titled “What is the Brinell hardness?”In the as-rolled condition, the Brinell hardness is between 175 HB and 240 HB.
What is the modulus of elasticity?
Section titled “What is the modulus of elasticity?”For annealed material at room temperature, Young’s modulus is 207.5 GPa (30.1 Msi), and it decreases to 147.5 GPa (21.4 Msi) at 871 °C (1600 °F).
What elongation can be expected?
Section titled “What elongation can be expected?”Elongation at break ranges from 30 % to 60 %, depending on the treatment condition.