Incoloy 825
UNS N08825
Overview
A nickel-iron-chromium alloy with additions of molybdenum, copper, and titanium. Designed for superior resistance to both reducing and oxidizing acids, including sulfuric and phosphoric. The copper addition provides excellent resistance to sulfuric acid — a key differentiator from Inconel 625. Widely used in chemical processing, pollution control, and pickling operations.
Chemical Composition (wt%)
| Element | Min | Max |
|---|---|---|
| Ni (Nickel) | 38 | 46 |
| Cr (Chromium) | 19.5 | 23.5 |
| Mo (Molybdenum) | 2.5 | 3.5 |
| Cu (Copper) | 1.5 | 3 |
| Ti (Titanium) | 0.6 | 1.2 |
| Fe (Iron) | 22 | — |
| C (Carbon) | — | 0.05 |
| Mn (Manganese) | — | 1 |
| Si (Silicon) | — | 0.5 |
Mechanical Properties
| Property | Value | Condition |
|---|---|---|
| Tensile Strength | ≥ 586 MPa (85 ksi) | — |
| Yield Strength (0.2%) | ≥ 241 MPa (35 ksi) | — |
| Elongation | ≥ 30% | — |
| Hardness | ≤ 22 HRC | annealed |
| Density | 8.14 g/cm³ | — |
Physical Properties
| Property | Value |
|---|---|
| Melting Range | 1370 – 1400 °C |
| Thermal Conductivity | 11.1 W/m·K (at 23°C) |
| Max Service Temp | 540°C |
Corrosion Resistance
Excellent resistance to sulfuric and phosphoric acids at all concentrations and temperatures. Outstanding resistance to chloride stress corrosion cracking. Performs well in seawater, reducing environments, and sour gas. The copper addition provides unique protection in sulfuric acid — a key advantage over other nickel alloys. Resistant to intergranular corrosion after welding.
Typical Applications
Related Standards
Available Products in This Material
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