1. Basic Information
- Grade: Incoloy 825
- UNS: N08825
- W.Nr.: 2.4858
- Alloy Type: Nickel-Iron-Chromium-Molybdenum-Copper austenitic alloy
- Key Characteristics: Excellent resistance to pitting, crevice corrosion and stress corrosion cracking (SCC), good mechanical properties at both room and elevated temperatures, outstanding resistance to reducing and oxidizing acids.
2. Chemical Composition (wt%, typical)
| Element | N08825 |
|---|---|
| Nickel (Ni) | 38.0 – 46.0 |
| Chromium (Cr) | 19.5 – 23.5 |
| Iron (Fe) | Balance |
| Molybdenum (Mo) | 2.5 – 3.5 |
| Copper (Cu) | 1.5 – 3.0 |
| Aluminum (Al) | ≤ 0.2 |
| Titanium (Ti) | 0.6 – 1.2 |
| Carbon (C) | ≤ 0.05 |
| Manganese (Mn) | ≤ 1.0 |
| Silicon (Si) | ≤ 0.5 |
| Sulfur (S) | ≤ 0.03 |
| Phosphorus (P) | ≤ 0.03 |
3. Mechanical Properties (Solution Annealed, Room Temperature)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 585 MPa |
| Yield Strength (0.2% offset) | ≥ 240 MPa |
| Elongation | ≥ 30 % |
| Hardness | ≤ HB 220 |
| Modulus of Elasticity | ~ 205 GPa |
4. Physical Properties
| Property | Value |
|---|---|
| Density | 8.14 g/cm³ |
| Melting Range | 1370 – 1400 °C |
| Thermal Expansion (20–100°C) | ~ 13.9 × 10⁻⁶ /°C |
| Thermal Conductivity | ~ 11.6 W/(m·K) |
| Magnetism | Non-magnetic |
5. Corrosion Resistance
Excellent resistance to chloride-induced stress corrosion cracking (SCC).
Superior resistance to pitting and crevice corrosion in halide environments.
Good performance in sulfuric acid, phosphoric acid, nitric acid, and organic acids.
High corrosion resistance in sour oil and gas environments (H₂S, CO₂, chlorides).
Good resistance to oxidation and carburization at elevated temperatures.
6. Fabrication & Welding
- Heat Treatment: Solution annealing at 925–1010°C, followed by rapid cooling.
- Weldability: Good. Recommended fillers: ERNiCrMo-3 / ENiCrMo-3.
- Formability: Good cold and hot formability.
- Machinability: Similar to austenitic stainless steels.
7. Standards & Specifications
ASTM B424, B163, B165, B514, B515, B516, B564, B775
ASME SB424, SB163, SB165, SB514, SB515, SB516, SB564, SB775
NACE MR0175 / ISO 15156
8. Typical Applications
Oil and gas production equipment in sour service
Chemical processing reactors, heat exchangers, and piping
Pickling industry components and acid handling systems
Flue gas desulfurization (FGD) scrubbers
Waste treatment and pollution control equipment
Seawater cooling systems and marine components
9. Short Description (for Product List)
Incoloy 825 (UNS N08825) is a nickel-iron-chromium alloy with additions of molybdenum and copper, offering excellent resistance to stress corrosion cracking, pitting, and crevice corrosion. It is widely used in chemical processing, oil & gas, and pollution control equipment.