Corrosion resistance properties of INCOLOY 800 alloy

Corrosion resistance properties of INCOLOY 800 alloy

 

Corrosion resistance properties of Incoloy 800 alloy

Incoloy 800 is a nickel-iron-chromium alloy known for its excellent high-temperature strength and resistance to oxidation, carburization, and sulfidation, making it ideal for furnace components, petrochemical cracking tubes, and heating element sheaths. It also exhibits good resistance to aqueous corrosion and chloride stress corrosion cracking. However, due to its higher iron content, its resistance to certain aggressive acids is not as good as alloys with higher nickel content (such as Incoloy 825).

What are the specifications of Incoloy 800?

The chemical composition of Incoloy 800HT alloy falls within the range of the 800H alloy, but with a narrower composition range and requiring heat treatment at a minimum of 2100°F (1149°C). Its carbon content is 0.06% to 0.10% (compared to 0.05% to 0.10% for 800H alloy), and the total aluminum and titanium content is 0.85% to 1.20% (compared to 0.30% to 1.20% for 800H alloy).

 

Incoloy 800 belongs to the nickel-iron-chromium alloy series and is designed for exceptional performance in high-temperature and corrosive environments. Engineers frequently choose Incoloy 800 because it maintains its strength and stability even at elevated temperatures. This alloy contains a balanced composition of nickel, iron, and chromium, which gives it its unique properties. Incoloy 800 alloy is renowned for its excellent oxidation and carburization resistance, making it a preferred material in industries such as power generation and chemical processing.

The table below summarizes the key performance data for Incoloy 800 alloy:

Incoloy 800H and Incoloy 800HT are two commonly used grades. Both alloys possess higher creep strength and rupture strength, making them suitable for more demanding applications. Due to their durability and corrosion resistance, Incoloy 800 tubing products are widely used in heat exchangers.

Physical Properties of Incoloy 800

Mechanical Properties of Incoloy 800

Incoloy 800 Forms and Standards

High-Performance Alloy
INCOLOY 800 alloy is renowned for its high-performance superalloy characteristics, enabling it to resist corrosion in some of the harshest environments. This is all thanks to its unique composition. The high nickel content provides good resistance to sulfidation, the iron content reduces the risk of internal oxidation, and the chromium exhibits excellent resistance to oxidation and general corrosion. The critical chemical balance of Incoloy 800 alloy makes it exceptionally resistant to various forms of corrosion. This includes resistance to scaling and stress corrosion cracking, particularly chloride stress corrosion cracking due to the formation of metal chlorides.

In many cases, the corrosion rate of Incoloy 800 alloy initially increases rapidly and then gradually levels off. This is because the polarization resistance increases with increasing exposure time. Ultimately, this results in a corrosion rate for INCOLOY 800 alloy that is significantly lower than that of 304 stainless steel, making it a superior choice for certain applications.

Studies have found that Incoloy 800 alloy exhibits high corrosion resistance when exposed to molten carbonates, molten eutectic salt deposits, hydrogen peroxide, and hydrogen chloride in humid air. Although research in this area may be limited, studies conducted by the Nickel Institute indicate that it also has high resistance to sulfuric acid, with a corrosion rate of only 0.51 mm/year (20 mils/year) when exposed to 5% sulfuric acid at 50 degrees Celsius.

Enhanced Corrosion Resistance
As briefly mentioned earlier, Incoloy 800 alloy is the basis for many other nickel alloys. The closest of these is the 800H alloy. In fact, Incoloy 800 and Incoloy 800H are so similar that they were once both classified as Incoloy 800 alloy, one designated "Grade 1" and the other "Grade 2." Grade 2 had a slightly higher carbon content than Grade 1 and was later designated Incoloy 800H.

Incoloy 800HT is simply a variant of this high-carbon alloy, containing higher levels of aluminum and titanium. Due to the addition of these elements, better corrosion resistance is achieved even at higher temperatures (well above 816 degrees Celsius). Incoloy 800H and 800HT alloys have a corrosion rate of 0.15 mm/year or 6.0 mils/year in refinery furnaces. In comparison, 310 stainless steel has a corrosion rate of 0.23 mm/year or 8.9 mils/year in the same environment. 309 stainless steel has a corrosion rate of 2.15 mm/year or 84.5 mils/year. 304 stainless steel would completely oxidize in this environment.

Incoloy 825 alloy is perhaps the most different from Incoloy 800 alloy. Due to the addition of molybdenum and copper, it is a denser alloy with even higher corrosion resistance. The higher nickel content improves overall corrosion resistance, while the addition of molybdenum enhances resistance to sulfuric and phosphoric acids. The addition of copper enhances corrosion resistance at room temperature, making Incoloy 825 alloy a common choice for applications requiring corrosion resistance at varying temperatures.

Why Choose Gnee as Your Nickel-Based Alloy Supplier

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📦 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

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Gnee Steel also supplies custom incoloy 800 products in various sizes and specifications. Please send us your drawings for a quote!

Incoloy 800 alloy

Incoloy 800 alloy Pipe Packing