Incoloy® 825
Incoloy 825 is a titanium-stabilized fully austenitic nickel-iron-chromium alloy with additions of copper and molybdenum. It is specifically engineered to provide exceptional resistance to aggressive corrosive environments where Alloy 800 performs poorly.
- Common Forms: Pipe, Tube, Plate, Round Bar, Flanges, Fittings.
- Key Feature: Superior resistance to Sulfuric and Phosphoric acids.
- Stress Corrosion: Virtually immune to chloride-ion stress-corrosion cracking.
- Standard: ASTM B423 (Pipe), B424 (Plate), B425 (Bar).
The chemical composition of Incoloy 825 is balanced to provide resistance to a variety of corrosive conditions. The combination of Nickel, Molybdenum, and Copper allows it to withstand reducing environments such as those containing sulfuric and phosphoric acids.
Acid Resistance
Excellent resistance to sulfuric and phosphoric acids, making it the standard choice for heating coils, tanks, and crates in chemical processing.
Stress Corrosion Cracking
The high nickel content provides superb resistance to chloride-ion stress-corrosion cracking, a common failure mode in stainless steels like 316L.
Intergranular Attack
Stabilized with Titanium to prevent sensitization during welding. This ensures the material remains resistant to intergranular corrosion after fabrication.
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 38.0 - 46.0 |
| Iron (Fe) | 22.0 min (Balance) |
| Chromium (Cr) | 19.5 - 23.5 |
| Molybdenum (Mo) | 2.5 - 3.5 |
| Copper (Cu) | 1.5 - 3.0 |
| Titanium (Ti) | 0.6 - 1.2 |
| Carbon (C) | 0.05 max |
| Product Form | ASTM / ASME Standards |
|---|---|
| Pipe & Tube (Seamless) | ASTM B423, ASME SB423 |
| Pipe & Tube (Welded) | ASTM B704, ASTM B705, ASME SB704 |
| Plate, Sheet, Strip | ASTM B424, ASME SB424 |
| Bar & Rod | ASTM B425, ASME SB425 |
| Fittings | ASTM B366, ASME SB366 |
| Forgings | ASTM B564, ASME SB564 |
| Property | Typical Values (Room Temp) |
|---|---|
| Tensile Strength | 85 ksi (586 MPa) min |
| Yield Strength (0.2% Offset) | 35 ksi (241 MPa) min |
| Elongation | 30% min |
| Hardness | 135 - 165 HB |
Chemical Processing
Heat exchangers, evaporators, scrubbers, and piping handling sulfuric acid, phosphoric acid, and nitric acid.
Oil & Gas
Used in "sour gas" service (H2S environments) for downhole piping and wellhead components.
Pollution Control
Components in flue gas desulfurization (FGD) systems where sulfur and acid condensate are present.
Pickling Operations
Heating coils, tanks, crates, and baskets used in steel pickling lines (Sulfuric Acid baths).
In Need of Incoloy 825 Materials?
We maintain a robust inventory of Incoloy 825 pipes, plates, and bars. Contact us for certifications (MTR) and competitive pricing.
Get a Quick Quote