Which material is better, Incoloy 800 or Incoloy 840?
Which material is better, Incoloy 800 or Incoloy 840?
Incoloy 800 (and its high-temperature versions 800H/HT) offers excellent strength, creep resistance, and overall corrosion resistance, making it suitable for demanding chemical and power generation applications. Incoloy 840, on the other hand, is specifically alloyed with titanium, providing superior resistance to thermal fatigue, oxidation, and carburization, making it ideal for electric heating elements and furnace components. Choose 800 if you require extremely high heat resistance and strength; choose 840 if you need to withstand repeated heating/cooling cycles and require good oxidation resistance.
What are the temperature limits for Incoloy 800?
If the deformation is 5% or greater, the hot working temperature range for Incoloy 800H and 800HT alloys is 1740–2190°F (950–1200°C). If the degree of hot deformation is less than 5%, the recommended hot working temperature range is 1560–1920°F (850–1050°C).
What is Incoloy 840?
Incoloy 840 is a nickel-based stainless steel alloy used in heat treatment systems. It possesses excellent high-temperature resistance and reliable oxidation resistance, making it perform exceptionally well under cyclic heating conditions. The alloy maintains stable oxidation resistance even at operating temperatures above 980°C. Characteristics of the Incoloy 840 alloy include strong stress resistance in high-temperature environments. Incoloy 840 sheet products are commonly used in heaters, electric furnaces, and corrosive exhaust systems.
What is Incoloy 800?
Incoloy 800 is an iron-nickel-chromium alloy known for its excellent mechanical stability at high temperatures. It performs well in high-pressure, high-temperature chemical environments where oxidation and cracking frequently occur. The alloy maintains a balanced corrosion resistance while retaining high tensile strength during long-term use. It is widely used in petrochemical processing plants, heat treatment, heat exchangers, pressure boilers, and superheater tubing.
Comparison table of chemical compositions for Incoloy 840 and Incoloy 800
| Element | Incoloy 800 | Incoloy 840 |
|---|---|---|
| Carbon (C) | 0.10 | 0.08 |
| Manganese (Mn) | 1.50 | 1.00 |
| Phosphorus (P) | 0.045 | 0.03 |
| Sulfur (S) | 0.015 | 0.015 |
| Silicon (Si) | 1.00 | 1.00 |
| Chromium (Cr) | 19.0–23.0 | 18.0–22.0 |
| Nickel (Ni) | 30.0–35.0 | 18.0–22.0 |
| Molybdenum (Mo) | - | - |
| Titanium (Ti) | - | 0.60 |
| Copper (Cu) | 0.75 | 0.75 |
| Aluminum (Al) | 0.15–0.60 | 0.60 |
Mechanical property requirements for Incoloy 840 and Incoloy 800
|
Grade |
Tensile Strength MPa |
Yield Strength MPa |
Elongation % |
|
Incoloy 800 |
87(600) |
39.9(275) |
45 |
|
Alloy 840 |
83(572) |
35(241) |
40 |
Incoloy 800 Properties
Incoloy 800 is a nickel-chromium alloy with good strength and excellent oxidation and carburization resistance at high temperatures. It also exhibits excellent resistance to stress corrosion cracking and is relatively easy to weld. Incoloy 800 can be used at temperatures up to 1100°F (593°C). It is considered an age-hardening alloy because its strength increases over time. Due to its excellent corrosion resistance, Incoloy 800 is frequently used in heat exchangers, pressure vessels, and other components exposed to corrosive environments.
Incoloy 840 Properties
Unlike Incoloy 800, Incoloy 840 is an austenitic alloy containing chromium, nickel, and molybdenum. This alloy exhibits good resistance to reducing and oxidizing acids, as well as stress corrosion cracking and pitting. This makes it an ideal choice for petrochemical applications, such as pump shafts or turbine blades, where components must withstand corrosive chemicals for extended periods without corrosion or degradation. However, unlike Incoloy 800, it is not an age-hardening alloy, so its strength does not increase over time. Furthermore, it can only be used at temperatures up to 1000°F (538°C).
Main differences between Incoloy 800 and Incoloy 840
Incoloy 800 (especially 800H/HT) is designed for high strength, creep resistance, and fracture resistance in harsh thermal/chemical environments.
Incoloy 840 is designed to provide excellent high-temperature oxidation resistance, which is a common failure mode for heating elements.
Choose Incoloy 800 if structural integrity and high strength are required; choose Incoloy 840 if excellent oxidation resistance in heating applications is needed.
Incoloy 800 and Incoloy 840 Applications
Incoloy 840 Applications
Electric Heating: Used in heating elements and tubular heaters due to its stable resistance in high-temperature heating devices. Its oxidation resistance reduces scaling during continuous heating.
Heat Treatment: It is the preferred material for annealing furnace components and industrial heating systems; this alloy resists deformation and maintains structural stability under repeated temperature cycling.
Chemical and Petrochemical: Suitable for heating chemical pipelines and exhaust systems handling corrosive gases, as its corrosion resistance ensures safe handling of acidic fumes.
Power Generation: Suitable for heat exchangers and superheated steam equipment. This alloy performs well in components subjected to thermal expansion and high-temperature steam pressure.
Oil and Gas: Used in catalytic converter components and process heaters. This alloy withstands toxic exhaust gases without surface damage.
Incoloy 800 Applications Comparison
Petrochemical and Chemical Processing: This alloy is chosen for ethylene cracking, pressure piping, and heat exchangers. It remains stable in high-temperature hydrocarbon and process chemical environments.
Power Generation: Ideal for superheater tubes and boiler components that require prolonged exposure to high temperatures. It maintains mechanical strength without deformation.
Heat Treatment: Used in furnace linings, trays, and baskets. It withstands continuous heating without scaling or warping.
Aerospace: Suitable for thermal control components operating at extremely high temperatures. Maintains consistent strength during high-temperature load cycles.
Oil and Gas: Used in process heaters and refining systems. High resistance to acidic gases prevents high-temperature corrosion processes.
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 is a supplier of incoloy 800 alloy, offering a wide range of products including: seamless pipe (sizes: 4-219 mm; thickness: 0.5-20 mm); welded pipe (sizes: 5.0-1219.2 mm; thickness: 0.5-20 mm); plates (thickness: 0.1 to 100 mm; width: 10-2500 mm); strips; alloy round bars (diameter: 3-800 mm); flat bars (thickness: 2-100 mm; width: 10-500 mm); hexagonal bars (size: 2-100 mm); wire rods; and extruded profiles. We collaborate with steel mills to provide our customers with incoloy 800 alloy products that meet or exceed numerous leading industry standards, including ASTM, ASME, SAE, AMS, ISO, DIN, EN, and BS standards.
Gnee Steel stocks and sells incoloy 800, pipes, plates, strips, round bars, flat bars, forged billets, hexagonal steel, wire rods, and extruded profiles. Please feel free to contact us at ss@gneesteel.com for a quote.
