What are the differences between Inconel 600 and Incoloy 825?
What are the differences between Inconel 600 and Incoloy 825?
Inconel 600 is a high-nickel alloy (containing approximately 72% nickel) characterized by high strength and excellent high-temperature oxidation resistance, making it ideal for furnace components. Incoloy 825, on the other hand, is a nickel-iron-chromium alloy with a lower nickel content (approximately 40%), but the addition of elements such as molybdenum, copper, and titanium gives it superior corrosion resistance to specific corrosive media such as sulfuric acid. Therefore, it is more suitable for applications where acid/chloride corrosion is a critical factor, such as chemical processing, pickling, and marine environments, thus striking a balance between performance and cost. In short, Inconel 600 excels in extreme high-temperature/high-strength environments, while Incoloy 825 performs exceptionally well in harsh chemical/acidic corrosive environments.
What are the uses of Inconel 600?
It is used in the manufacture of reactors, muffle furnaces, roller hearth furnaces and other furnace components, as well as heat treatment baskets and trays. In the aerospace industry, INCONEL 600 alloy is used to manufacture various engine and airframe components that must withstand high temperatures. Examples include locking wires, exhaust pipe liners, and turbine seals.
Inconel 600 (UNS N06600)
Main uses: Extremely high temperatures, oxidizing environments, reducing atmospheres, nuclear industry.
Composition: High nickel (approx. 72%), chromium (approx. 14-17%), iron.
Main advantages: Excellent high-temperature strength, forms a stable oxide layer, suitable for nuclear industry/aerospace applications.
Disadvantages: Compared to Incoloy 825, it has poorer corrosion resistance to certain acids such as sulfuric acid.
The main alloying elements of Inconel 600 and Incoloy 825 and their functions
| Element | Inconel 600 | Incoloy 825 | Impact on Alloy Performance |
|---|---|---|---|
| Nickel (Ni) | ~72% | 38-46% | Offers corrosion resistance and durability |
| Chromium (Cr) | 14-17% | 19.5-23.5% | Enhances oxidation resistance; higher in Incoloy 825 provides better resistance to some acids |
| Iron (Fe) | Balance (~6-10%) | 38-46% | Provides structural support; higher in Incoloy 825 |
| Molybdenum (Mo) | Trace or none | 2.5-3.5% | Improves resistance to pitting, crevice corrosion, and reducing environments (sulfuric, phosphoric acids) |
| Copper (Cu) | Trace or none | 1.5-3.0% | Enhances resistance to reducing agents and acids |
| Titanium (Ti) | Trace or none | Up to 0.4% | Stabilizes against intergranular corrosion |
| Manganese (Mn) | Small amounts | Small amounts | Generally controlled to limit detrimental effects |
| Silicon (Si) | Small amounts (strictly controlled) | Small amounts | Affects oxidation and mechanical properties |
Incoloy 825 (UNS N08825)
Main uses: Sulfuric and phosphoric acids, chlorides, pickling equipment, chemical processing.
Composition: Nickel (approx. 38-46%), chromium (approx. 20-23%), iron (approx. 22-30%), also contains molybdenum and copper.
Main advantages: Excellent corrosion resistance to specific chemicals (acids/chlorides), good resistance to stress corrosion cracking.
Comparison of the chemical composition of Inconel 600 and Incoloy 825
| Element | Inconel 600 (UNS N06600) | Incoloy 825 (UNS N08825) |
|---|---|---|
| Nickel (Ni) | ≥ 72.0 % | 38.0 – 46.0 % |
| Chromium (Cr) | 14.0 – 17.0 % | 19.5 – 23.5 % |
| Iron (Fe) | 6.0 – 10.0 % | ≥ 22.0 % |
| Molybdenum (Mo) | – | 2.5 – 3.5 % |
| Copper (Cu) | ≤ 0.5 % | 1.5 – 3.0 % |
| Titanium (Ti) | – | 0.6 – 1.2 % |
| Aluminum (Al) | – | ≤ 0.2 % |
| Manganese (Mn) | ≤ 1.0 % | ≤ 1.0 % |
| Carbon (C) | ≤ 0.15 % | ≤ 0.05 % |
| Silicon (Si) | ≤ 0.5 % | ≤ 0.5 % |
| Sulfur (S) | ≤ 0.015 % | ≤ 0.03 % |
| Phosphorus (P) | – | ≤ 0.03 % |
Comparison of the mechanical properties of Inconel 600 and Incoloy 825
| Property | Inconel 600 (Annealed) | Incoloy 825 (Annealed) |
|---|---|---|
| Tensile Strength (MPa, min) | 550 – 690 | 586 – 724 |
| Yield Strength (0.2% Offset, MPa, min) | 240 | 241 – 345 |
| Elongation (% in 50 mm, min) | 30 | 30 |
| Hardness (Rockwell B, max) | 90 HRB | 88 HRB |
| Density (g/cm³) | 8.47 | 8.14 |
| Melting Range (°C) | 1370 – 1425 | 1370 – 1400 |
| Primary Corrosion Resistance | Oxidation, chlorides, alkalis | Acids, chlorides, seawater |
| Typical Continuous Service Temperature (max) | ~700°C | ~540°C |
Industrial Applications and Suitability
Inconel 600 Applications
Chemical Processing
Inconel 600 is widely used in the chemical processing industry due to its excellent oxidation resistance and high-temperature corrosion resistance. It is suitable for applications exposed to corrosive chemicals and extreme temperatures, such as reactors, evaporators, and heat exchangers. The alloy's stability and durability under thermal stress make it an ideal choice for maintaining integrity in corrosive chemical environments.
Heat Treatment
The high-temperature strength and oxidation resistance of Inconel 600 make it ideal for heat treatment applications, such as furnace components, heat treatment baskets, and fixtures. The alloy can withstand prolonged exposure to high temperatures without significant degradation, ensuring longevity and reliability during heat treatment processes.
Marine Environments
Inconel 600 is also used in marine environments due to its excellent corrosion resistance to seawater and saline atmospheres. Its resistance to stress corrosion cracking and pitting makes it suitable for marine engineering applications, including offshore platforms and naval equipment.
Furnace Components
Inconel 600 is widely used in furnace components due to its ability to maintain mechanical properties at high temperatures. It is an ideal material for manufacturing furnace components such as muffles, retorts, and radiant tubes. The alloy's resistance to carburization and oxidation enhances its performance and lifespan in high-temperature furnace environments.
Incoloy 825 Applications
Chemical Processing
Incoloy 825 performs exceptionally well in chemical processing applications, particularly in environments containing sulfuric and phosphoric acids. Its enhanced resistance to pitting, crevice corrosion, and stress corrosion cracking makes it suitable for reactors, heat exchangers, and piping systems. The alloy's ability to withstand corrosive chemical environments ensures reliable performance and reduces maintenance costs.
Heat Treatment
Incoloy 825 is also used in heat treatment applications, but it is more suited to environments where corrosion resistance is critical rather than extreme high temperatures. The alloy's resistance to various forms of corrosion, including intergranular corrosion, makes it a reliable material for heat exchangers and other components in chemical plants.
Marine Environments
Incoloy 825 exhibits excellent resistance to chloride-induced stress corrosion cracking, making it highly suitable for marine environments. It is commonly used in the construction of seawater cooling systems, ship exhaust systems, and other components exposed to saltwater. This alloy exhibits excellent durability in chloride-rich environments, ensuring its long-term performance and resistance to degradation.
Why Choose Gnee as Your Nickel-Based Alloy Supplier
✅ Over 18 years of export experience, products sold to more than 80 countries
✅ Certified by ISO, SGS, and BV
✅ Global inventory of Inconel, Hastelloy, Incoloy, and Monel alloy tubing, plates, and bars
✅ Custom processing services available – including cutting, polishing, CNC machining, and packaging
✅ Fast delivery within 7-15 days, supported by global logistics partners
📦 Packaging and Shipping
All stainless steel products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
Gnee Steel also supplies custom Inconel 600 products in various sizes and specifications. Please send us your drawings for a quote!
