Corrosion Resistant Incoloy 825 Alloy Bar Alloy 825 UNS N08825 For Chemical Processing
Incoloy 825 is a nickel-iron-chromium alloy engineered for exceptional corrosion resistance in a wide range of demanding environments. The chemical composition of this nickel-based alloy, fortified with molybdenum, copper, and titanium, provides superior performance against reducing acids like sulfuric and phosphoric acid, as well as oxidizing media such as nitric acid.
Unlike many corrosion-resistant alloys that excel only in specific environments, Incoloy 825 offers balanced resistance to both reducing and oxidizing acids. The addition of molybdenum and copper provides outstanding protection against pitting and crevice corrosion, while titanium stabilization ensures immunity to intergranular attack. With a minimum nickel content of 38%, Alloy 825 also offers proven resistance to chloride-induced stress-corrosion cracking.
This combination of properties makes a premier material for critical applications across chemical processing, pollution control, offshore oil and gas, and marine engineering. Common trade names include Incoloy 825, Alloy 825, Nickelvac 825, and Nicrofer 4241.
Key advantages:
- Broad Corrosion Resistance: Excellent resistance to both reducing and oxidizing acids
- Stress-Corrosion Cracking Resistance: High nickel content (38-46%) provides proven SCC resistance
- Pitting & Crevice Corrosion Resistance: Molybdenum and copper additions enhance localized corrosion protection
- Intergranular Attack Immunity: Titanium stabilization prevents weld decay and sensitization
- Versatile Fabricability: Excellent weldability and formability using standard techniques
- NACE MR0175 Approved: Certified for oil and gas service in sour environments
| Parameter | Details |
|---|---|
| Product Name | Incoloy 825 / Alloy 825 / Incoloy® 825 |
| UNS Designation | N08825 |
| Werkstoff Number | 2.4858 |
| EN Designation | NiCr21Mo |
| Common Trade Names | Nickelvac 825, Nicrofer 4241, Incoloy 825 |
| Product Forms | Plate, Sheet, Strip, Rod, Bar, Wire, Seamless Pipe, Welded Pipe, Seamless Tube, Welded Tube, Forgings, Forging Stock, Hexagon |
| Supply Condition | Annealed |
| Available Dimensions | Sheet/Plate: 0.3mm – 50mm thickness; Tube: 6mm – 219mm OD (custom available) |
| Standard Length | 2000mm, 2438mm, 3000mm, 6000mm (or as required) |
| Custom Sizes | Available upon request |
| Surface Finish | Annealed, Pickled, Descaled |
| NACE Compliance | NACE MR0175 (for oil and gas service) |
The chemical composition of Incoloy 825 complies with ASTM B425, B424, and B423 standards.
| Element | Content (%) | Role |
|---|---|---|
| Nickel (Ni) | 38.0 – 46.0 | Provides SCC resistance and austenitic stability |
| Iron (Fe) | ≥ 22.0 (balance) | Base element |
| Chromium (Cr) | 19.5 – 23.5 | Enhances oxidation and corrosion resistance |
| Molybdenum (Mo) | 2.5 – 3.5 | Improves pitting and crevice corrosion resistance |
| Copper (Cu) | 1.5 – 3.0 | Provides resistance to reducing acids (sulfuric/phosphoric) |
| Titanium (Ti) | 0.6 – 1.2 | Stabilizes against intergranular attack |
| Carbon (C) | ≤ 0.05 | Minimized to prevent sensitization |
| Manganese (Mn) | ≤ 1.00 | Aids in hot workability |
| Silicon (Si) | ≤ 0.50 | Improves oxidation resistance |
| Aluminum (Al) | ≤ 0.20 | Deoxidizer |
| Sulfur (S) | ≤ 0.03 | Controlled for hot workability |
| Phosphorus (P) | ≤ 0.03 | Minimized to maintain ductility |
Actual mill test certificates (EN 10204 3.1) available per batch.
Key Composition Features:
- High Nickel (38-46%): Provides excellent resistance to chloride stress-corrosion cracking
- Molybdenum + Copper: Unique combination for resistance to both reducing and oxidizing environments
- Titanium Stabilization: Prevents the risk of intergranular corrosion after welding
Room Temperature Properties (Annealed Condition)
| Property | Metric (MPa) | Imperial (ksi) |
|---|---|---|
| Tensile Strength (Rm) | ≥ 586 | ≥ 85 |
| Yield Strength 0.2% Proof (Rp0.2) | ≥ 241 | ≥ 35 |
| Elongation (A) | ≥ 30% | ≥ 30% |
| Density | 8.14 g/cm³ | 0.294 lb/in³ |
| Melting Point | 1370 – 1400°C | 2500 – 2550°F |
| Modulus of Elasticity | 196 GPa | 28.4 x 10³ ksi |
Typical Mechanical Properties by Product Form (Annealed)
| Product Form | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
| Tube | 772 | 441 | 36 |
| Tube (Cold Drawn) | 1000 | 889 | 15 |
| Bar | 690 | 324 | 45 |
| Plate | 662 | 338 | 45 |
| Sheet | 758 | 421 | 39 |
Physical Properties:
- Electrical Resistivity: 1.14 µΩ·m (at 20°C)
- Thermal Conductivity: 11.1 W/m·K (at 20°C)
- Coefficient of Thermal Expansion: 14.0 µm/m·K (20-100°C)
- Specific Heat Capacity: 440 J/kg·K (at 20°C)
Incoloy 825 is available in all standard mill forms and complies with international specifications. The alloy is also listed in NACE MR0175 for oil and gas service.
Rod, Bar, Wire, Forgings, and Forging Stock
| Standard | Specification |
|---|---|
| ASTM | B425, B564 |
| ASME | SB425, SB564 |
| BS | BS 3076NA16 |
| DIN | DIN 17752, DIN 17753, DIN 17754 |
| VdTÜV | VdTÜV 432 |
| ISO | ISO 9723, ISO 9724, ISO 9725 |
Plate, Sheet, and Strip
| Standard | Specification |
|---|---|
| ASTM | B424, B906 |
| ASME | SB424, SB906 |
| BS | BS 3072NA16, BS 3073NA16 |
| DIN | DIN 17750 |
| VdTÜV | VdTÜV 432 |
| ISO | ISO 6208 |
Pipe and Tube
| Standard | Specification |
|---|---|
| ASTM | B163, B423, B704, B705, B751, B775, B829 |
| ASME | SB163, SB423, SB704, SB705, SB751, SB775, SB829 |
| BS | BS 3074NA16 |
| DIN | DIN 17751 |
| VdTÜV | VdTÜV 432 |
| ISO | ISO 6207 |
Other Forms
| Product | Standard |
|---|---|
| Fittings | ASTM B366, ASME SB366 |
| General | DIN 17744 |
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