Overview
Incoloy 825 is a superalloy with molybdenum and copper added on the basis of Incoloy 800.
This makes alloy 825 superior to alloy 800 in corrosion resistance.
In this article, we will discuss in detail the performance comparison between Incoloy 800 and Incoloy 825.
Basic Information
Name
Incoloy 800
UNS N08800
W.Nr. 1.4876
Brand
INCOLOY®
Matrix
Type
Solid Solution
Strengthened Alloy
Density
7.94 g/cm³
Use Temperature
High Temperature
Name
Incoloy 825
UNS N08825
W.Nr. 2.4858
Brand
INCOLOY®
Matrix
Type
Solid Solution
Strengthened Alloy
Density
8.14 g/cm³
Use Temperature
High Temperature
Introduction
Incoloy 800
INCOLOY alloy 800 (UNS N08800 / W.Nr. 1.4876) is a widely used material for construction of equipment requiring corrosion resistance, heat resistance, strength, and stability for service up to 1500°F (816°C). Alloy 800 offers general corrosion resistance to many aqueous media and, by virtue of its content of nickel, resists stress corrosion cracking. At elevated temperatures it offers resistance to oxidation, carburization, and sulfidation along with rupture and creep strength.
Incoloy 825
INCOLOY® alloy 825 (UNS N08825 / W.Nr. 2.4858) is a nickel-iron-chromium alloy with additions of molybdenum, copper, and titanium. The alloy’s chemical composition is designed to provide exceptional resistance to many corrosive environments. The resistance of INCOLOY alloy 825 to general and localized corrosion under diverse conditions gives the alloy broad usefulness.
Chemical Composition
Purity
Incoloy 800
lose
Incoloy 825
WIN
Compared with Incoloy 800, Incoloy 825 has a higher degree of purity and stricter control of harmful elements.
The following will analyze the different harmful elements one by one:
Sulfur
The sulfur content has a great influence on the transient performance of the alloy. The sulfur content control of alloy 800 is stricter than that of 825, so in general, alloy 800 has better transient performance than 825.
Silicon and Manganese
In contrast, the silicon content and manganese content more affect the durability of the alloy at high temperatures. Alloy 825 has better control of these two impurity elements. This means that alloy 825 has better durability.
Overall, alloy 825 still has better control of impurity elements.
Corrosion Resistance
Incoloy 800
Lose
Incoloy 825
Win
NICKEL
Alloy 825 has less iron content and more nickel content. This means that its basic corrosion resistance is better.
Chromium
Both alloys have a large amount of chromium, which guarantees their good oxidation resistance.
Molybdenum
Molybdenum is added to alloy 825. Therefore, it has more resistance to reducing environment (sulfuric and phosphoric acids) than alloy 800. The molybdenum also aids resistance to pitting and crevice corrosion.
Copper
In addition, the more copper element in Incoloy 825 also makes it further have excellent corrosion resistance at room temperature.
Taken together, alloy 825 has stronger corrosion resistance than alloy 800 in all aspects.
Mechanical Behavior
Incoloy 800
Tie
Incoloy 825
Tie
Molybdenum
Both Incoloy 800 and Incoloy 825 are solid solution strengthened alloys. Because some molybdenum is added to 825 to make the solid solution strengthening effect better, its overall strength will be higher. But there is no obvious difference in strength between the two alloys. They mainly differ in corrosion resistance.
Physical Properties
| Incoloy 800 | Incoloy 825 | |
|---|---|---|
| Density, g/cm³ | 7.94 | 8.14 |
| Density, lb/in.³ | 0.287 | 0.294 |
| Melting Range, °F | 2475-2525 | 2500-2550 |
| Melting Range, °C | 1357-1385 | 1370-1400 |
| Permeability at 200 oersted (15.9 kA/m) | 1.009-1.014 | 1.005 |
| Curie Temperature, °F | -175 | <-320 |
| Curie Temperature, °C | -115 | <-196 |
Application
It can be seen that Incoloy 800 is only used for those high temperature applications, while Incoloy 825 is widely used in highly corrosive environments.
Supported Products
Incoloy 800
Main Standards
Incoloy 800
Condenser and Heat Exchanger Tube: ASTM B163
Seamless Pipe and Tube: ASTM B407, ASTM B829
Welded Pipe: ASTM B514, ASTM B775
Welded Tube: ASTM B515, ASTM B751
Welded Fittings: ASTM B366
Rod and Bar: ASTM B408
Forgings: ASTM B564
Plate, Sheet, and Strip: ASTM A240, ASTM A480,
ASTM B409, ASTM B906
Incoloy 825
Condenser and Heat Exchanger Tube: ASTM B163
Seamless Pipe and Tube: ASTM B423, ASTM B829
Welded Pipe: ASTM B705, ASTM B775
Welded Tube: ASTM B704, ASTM B751
Welded Fittings: ASTM B366
Rod and Bar: ASTM B425
Forgings: ASTM B564
Plate, Sheet, and Strip: ASTM B424, ASTM B906
Price
Incoloy 800
LOW
Incoloy 825
high
Since Incoloy 825 has better corrosion resistance and more complex composition than Incoloy 800, its price will be slightly higher than Incoloy 800.
In some high-temperature applications where the environment is not very harsh, alloy 800 is recommended to save costs.
Conclusion
Since Incoloy 825 adds molybdenum and copper elements on the basis of Incoloy 800, its comprehensive corrosion resistance is better than that of alloy 800. Therefore, it is widely used in various complex environments.
Both alloys are solid solution strengthened alloys, and there is no decisive difference in mechanical properties.
The price of alloy 800 is lower, and it can be given priority when both alloys can be used.
AEETHER CO., LIMITED produce cost-effective Incoloy 800 and Incoloy 825 products. If you have corresponding needs, please do not hesitate to contact us:
