Whether you are a supplier or an end user of Inconel alloys, choosing between Incoloy 825 and Incoloy 925, or advising customers on material selection, can be challenging.
The Incoloy 825 and Incoloy 925 are both the Incoloy alloy family.
In this article, we will compare the performance differences between these two alloys from various perspectives.
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 nickel content is sufficient for resistance to chloride-ion stress-corrosion cracking. The nickel, in conjunction with the molybdenum and copper, also gives outstanding resistance to reducing environments such as those containing sulfuric and phosphoric acids.
The molybdenum also aids resistance to pitting and crevice corrosion. The alloy’s chromium content confers resistance to a variety of oxidizing substances such as nitric acid, nitrates and oxidizing salt. The titanium addition serves, with an appropriate heat treatment, to stabilize the alloy against sensitization to intergranular corrosion.
The resistance of INCOLOY alloy 825 to general and localized corrosion under diverse conditions gives the alloy broad usefulness. Applications include chemical processing, pollution control, oil and gas recovery, acid production, pickling operations, nuclear fuel reprocessing, and handling of radioactive wastes. Applications for alloy 825 are similar to those for INCOLOY alloy 020.
What is Incoloy Alloy 925?
Incoloy alloy 925 (UNS N09925) is an agehardenable nickel-iron-chromium alloy with additions of molybdenum, copper, titanium and aluminum. The titanium and aluminium are specifically added to give a strengthening of the alloy during ageing, as Ni3(Al, Ti) gamma (‘ϒ’) prime precipitates form throughout the alloy matrix and greatly increases the hardness and strength in a similar way to alloy 718 and Inconel alloy 725.
The alloy is designed to provide a combination of high strength and
excellent corrosion resistance. The nickel content is sufficient for protection against chloride-ion stresscorrosion cracking.
The nickel, in conjunction with the molybdenum and copper, also gives outstanding resistance to reducing chemicals. The molybdenum aids
resistance to pitting and crevice corrosion.
The alloy’s chromium content provides resistance to oxidizing environments. The titanium and aluminum additions cause a strengthening reaction during heat treatment.
Incoloy alloy 925 is used in various applications requiring a combination of high strength and corrosion resistance. Because of the alloy’s resistance to sulfide stress cracking and stress-corrosion cracking in “sour” (H2S containing) crude oil and natural gas, it is used for down-hole and surface gaswell components including tubular products, valves, hangers, landing nipples, tool joints and packers.
The alloy is also useful for fasteners, marine and pump shafting and high-strength piping systems.
Incoloy Alloy 825 vs Incoloy Alloy 925 Chemical Composition
Here’s a comparison table for the chemical composition of Incoloy Alloy 825 and Incoloy Alloy 925:
Incoloy Alloy 825 vs Incoloy Alloy 925 Corrosion Resistance
In nickel alloys, nickel itself provides excellent corrosion resistance, making both Incoloy 825 and Incoloy 925 highly effective in corrosive environments.
Incoloy 825 has a higher chromium content than Incoloy 925, enhancing its oxidation resistance.
Incoloy Alloy 825 vs Incoloy Alloy 925 Mechanical Behavior
Incoloy 825 Mechanical Properties
| Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 8.14 g/cm3 | 1400 °C (2550 °F) | 690-1000Mpa | 330-880Mpa | 45% – 15% |
Incoloy 925 Mechanical Properties
| Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 8.08 g/cm3 | 1366 °C (2490 °F) | 1189Mpa | 832Mpa | 27% |
Incoloy Alloy 825 vs Incoloy Alloy 925 Application
The resistance of INCOLOY alloy 825 to general and localized corrosion under diverse conditions gives the alloy broad usefulness. Applications include chemical processing, pollution control, oil and gas recovery, acid production, pickling operations, nuclear fuel reprocessing, and handling of radioactive wastes.
INCOLOY alloy 925 is used in various applications requiring a combination of high strength and corrosion resistance.
Because of the alloy’s resistance to sulfide stress cracking and stress-corrosion cracking in “sour” (H2S containing) crude oil and natural gas, it is used for down-hole and surface gaswell components including tubular products, valves, hangers, landing nipples, tool joints and packers.
The alloy is also useful for fasteners, marine and pump shafting and high-strength piping systems.
Incoloy Alloy 825 vs Incoloy Alloy 925 Main Standards
Here’s a comparison table for the standards of Inconel alloy Incoloy Alloy 825 and Incoloy Alloy 925:
Incoloy Alloy 825 vs Incoloy Alloy 925 Cost
Since Incoloy 825 has better corrosion resistance and more complex composition than Incoloy 925, its price will be slightly higher than Incoloy 925.
In some high-temperature applications where the environment is not very harsh, alloy 925 is recommended to save costs.
Conclusion
Incoloy 925 is a cost-effective alternative to Incoloy 825, offering slightly lower purity, corrosion resistance, and mechanical properties. However, its lower price makes it a preferred choice for many applications.
We manufacture a wide range of nickel alloy products, including both Alloy 825 and Alloy 925. If you have any requirements, please feel free to send us an inquiry.
