What is the difference between Inconel 800 and 825?
What is Incoloy Alloy 825?
Incoloy Alloy 825 Plate, Incoloy Metal Sheet
Incoloy 825 is a nickel-iron-chromium alloy with added molybdenum, copper, and titanium. It is designed to provide excellent resistance to reducing and oxidizing acids, stress corrosion cracking, and pitting. Incoloy 825 is particularly well suited for chemical processing, pollution control, and oil and gas applications.
What is Incoloy Alloy 800?
Incoloy 800 is a nickel-iron-chromium alloy that offers excellent resistance to oxidation, carburization, and nitriding in high-temperature environments. It maintains its strength and stability at elevated temperatures, making it suitable for applications such as heat exchangers, furnace components, and petrochemical processing.
Incoloy 800 vs. 825 Alloy – What's the Difference?
Choosing between Incoloy 800 and Inconel Alloy 825 depends on several factors, including chemical composition, mechanical properties, and cost. Below, we break down the key differences:
Chemical Composition: Incoloy 800 vs 825 Alloy
| Element | Incoloy 800 | Incoloy 825 |
|---|---|---|
| Ni | 30–35% | 38–46% |
| Cr | 19–23% | 19.5–23.5% |
| Fe | Balance | Balance |
| Mo | – | 2.5–3.5% |
| Cu | – | 1.5–3% |
| Ti | ≤ 0.6% | 0.6–1.2% |
| C | ≤ 0.10% | ≤ 0.05% |
| Si | ≤ 1.0% | ≤ 0.5% |
| Mn | ≤ 1.5% | ≤ 1.0% |
Mechanical Behavior: Incoloy 800 vs 825 Alloy
| Property | Incoloy 800 | Incoloy 825 |
|---|---|---|
| Tensile Strength | ≥ 450 MPa | ≥ 550 MPa |
| Yield Strength | ≥ 170 MPa | ≥ 220 MPa |
| Elongation | ≥ 30% | ≥ 30% |
| Hardness (Rockwell) | B85–B90 | B88–B93 |
Physical Properties: Incoloy 800 vs 825 Alloy
| Property | Incoloy 800 | Incoloy 825 |
|---|---|---|
| Density | 7.94 g/cm³ | 7.94 g/cm³ |
| Melting Range | 1357–1385°C | 1370–1400°C |
| Thermal Conductivity | 11.2 W/m·K (at 100°C) | 11.1 W/m·K (at 100°C) |
| Specific Heat Capacity | ~502 J/kg·K | ~460 J/kg·K |
| Electrical Resistivity | 0.98 μΩ·m | 1.03 μΩ·m |
Applications
Incoloy 800: Ideal for high temperature industrial applications such as heat exchangers and furnace components.
Incoloy 825: Suitable for chemical processing, pollution control and environments where acid resistance is critical.
Heat Resistance
Designed for high temperature applications, Incoloy 800 can withstand temperatures up to 1100°C. Incoloy 825 can withstand high temperatures but is better known for its corrosion resistance.
Corrosion Resistance
Because Incoloy 825 contains molybdenum and copper, it performs better than Incoloy 800 in environments containing reducing agents such as sulfuric and phosphoric acids.
Cost
Incoloy 825 is generally more expensive because of its enhanced corrosion resistance and additional alloying elements. Incoloy 800 is more cost effective in high temperature but less corrosive conditions.
Main Standards
Incoloy 800: ASTM B409, ASTM B407
Incoloy 825: ASTM B424, ASTM B425
Fabrication and Weldability
Both alloys have high fabricability and weldability, but care must be taken with Incoloy 825 to avoid contamination during welding, as its corrosion resistance depends on maintaining the purity of the alloy.
Which is better? Incoloy 800 vs. 825 alloy
The choice between Incoloy 800 and 825 depends on your application requirements:
For high-temperature, structural integrity-critical applications, choose Incoloy 800.
In environments with corrosive media, especially acids, choose Incoloy 825.
