Inconel 625 is a corrosion- and oxidation-resistant nickel-based alloy with exceptional strength and toughness in high-temperature and high-pressure environments. It is widely used in aerospace, marine, chemical processing, and nuclear applications due to its excellent mechanical properties and resistance to a wide range of corrosive environments. Below is a comprehensive overview of Inconel 625’s material properties, including its chemical composition, mechanical characteristics, thermal performance, and corrosion resistance.
Chemical Composition of Inconel 625
| Element |
Content (%) |
| Nickel (Ni) |
58.0 min |
| Chromium (Cr) |
20.0 – 23.0 |
| Molybdenum (Mo) |
8.0 – 10.0 |
| Niobium (Nb) + Tantalum (Ta) |
3.15 – 4.15 |
| Iron (Fe) |
5.0 max |
| Carbon (C) |
0.10 max |
| Manganese (Mn) |
0.50 max |
| Silicon (Si) |
0.50 max |
| Phosphorus (P) |
0.015 max |
| Sulfur (S) |
0.015 max |
Mechanical Properties at Room Temperature
| Property |
Value |
Standard |
| Tensile Strength |
827 MPa (120 ksi) |
ASTM B443 |
| Yield Strength (0.2% Offset) |
414 MPa (60 ksi) |
ASTM B443 |
| Elongation |
≥30% |
ASTM B443 |
| Hardness |
≤100 HRB |
ASTM E18 |
Thermal Properties
| Property |
Value |
Temperature (°C) |
| Thermal Conductivity |
9.8 W/m·K |
Room Temperature |
| Specific Heat |
0.435 J/g·K |
Room Temperature |
| Electrical Resistivity |
1.31 μΩ·m |
Room Temperature |
| Melting Range |
1290 – 1350°C |
N/A |
| Coefficient of Expansion |
12.8 µm/m·K |
20–100°C |
Mechanical Properties at Elevated Temperatures
| Temperature (°C) |
Yield Strength (MPa) |
Tensile Strength (MPa) |
| 20 |
414 |
827 |
| 200 |
400 |
780 |
| 400 |
365 |
720 |
| 600 |
320 |
670 |
| 800 |
290 |
630 |
| 1000 |
260 |
590 |
Corrosion Resistance Features
| Environment |
Resistance |
| Seawater |
Excellent |
| Acids (Nitric, Sulfuric, Phosphoric) |
Excellent |
| Alkaline Solutions |
Very Good |
| Oxidizing & Reducing Environments |
Excellent |
| Chloride-ion stress corrosion cracking |
Highly Resistant |
Standards and Designations
| Standard |
Designation |
| UNS |
N06625 |
| ASTM |
B443, B564, B444 |
| AMS |
5666, 5599 |
| ISO |
ISO 6208 |
Frequently Asked Questions
1. What are the key mechanical properties of Inconel 625?
Inconel 625 offers a tensile strength of around 827 MPa, yield strength of 414 MPa, and elongation of 30% at room temperature.
2. What temperatures can Inconel 625 withstand?
It maintains structural integrity and strength up to 1000°C, with gradual reductions in yield and tensile strength at elevated temperatures.
3. What types of corrosion can Inconel 625 resist?
Inconel 625 shows excellent resistance to pitting, crevice corrosion, chloride-induced stress corrosion cracking, and both oxidizing and reducing chemical environments.
