Inconel 800 vs Incoloy 800: Composition, Properties, and Applications
When it comes to high-performance alloys, the names Inconel 800 and Incoloy 800 often surface in discussions about durability and…
When it comes to selecting the right alloy for high-temperature applications, the choice between Incoloy 800 and Incoloy 840 can be pivotal. Both alloys boast impressive properties, but understanding their subtle differences is crucial for making an informed decision. Are you curious about which alloy offers superior corrosion resistance, or how their tensile strengths compare? This article delves into the intricate details of their chemical compositions, mechanical properties, and practical applications. By the end, you’ll have a clear understanding of which Incoloy alloy stands out for your specific needs. So, which one is truly better suited for your next project? Let’s find out.
Incoloy 800 and Incoloy 840 are nickel-iron-chromium alloys known for their excellent resistance to oxidation and carburization in high-temperature environments. These alloys are widely used in industries where durability and resistance to harsh conditions are essential.
Incoloy 800 is a nickel-chromium alloy with significant iron content. It includes small amounts of copper and aluminum, which enhance its performance in corrosive environments. The high chromium content increases its resistance to oxidation, making it suitable for use in high-temperature applications like heat exchangers and furnace components.
Incoloy 840 is an austenitic alloy that includes chromium, nickel, molybdenum, copper, titanium, and aluminum, providing greater strength but also increased susceptibility to corrosion in acidic environments. It is commonly used in applications that require high strength and moderate resistance to corrosive environments, such as petrochemical and gas turbine components.
The primary difference lies in the presence of molybdenum, copper, titanium, and aluminum in Incoloy 840, which provides additional strength and specific performance characteristics.
Incoloy 800 has a tensile strength of around 95 ksi, while Incoloy 840 has a higher tensile strength of approximately 130 ksi. Incoloy 840 also has a higher yield strength (320 MPa) compared to Incoloy 800.
Incoloy 800 can withstand temperatures up to 1100°F (593°C) and has a melting point around 1425°C, making it age-hardenable. In contrast, Incoloy 840 is suitable for temperatures up to 1000°F (538°C) with a melting point around 1390°C and is not age-hardenable.
When choosing between Incoloy 800 and Incoloy 840, several factors must be considered:
Understanding these key differences and factors helps in making an informed decision when selecting the appropriate alloy for specific industrial applications.
Incoloy 800 and Incoloy 840 are both known for their excellent performance in high-temperature environments.
Incoloy 800 can withstand temperatures up to 1100°F (593°C), with variants handling up to 1800°F (982°C), making it suitable for heat exchangers and furnace components. This alloy’s ability to endure oxidation and carburization at elevated temperatures ensures its longevity and reliability in demanding conditions. Incoloy 800 is ideal for chemical processing equipment, power plant components, and industrial furnaces.
Incoloy 840 is typically used in environments up to 1000°F (538°C). Its high tensile strength makes it valuable for components such as gas turbines and petrochemical processing equipment. While it does not tolerate as high temperatures as Incoloy 800, it excels in moderate-temperature environments requiring high strength.
Both Incoloy 800 and Incoloy 840 offer excellent corrosion resistance, tailored to different environments.
Incoloy 800 resists oxidation, carburization, and chloride stress-corrosion cracking. Its high chromium content makes it effective in oxidizing environments, such as those involving nitric acid. This resistance is crucial for maintaining structural integrity in corrosive conditions, benefiting industries like chemical and petrochemical processing.
Incoloy 840 is designed to resist both reducing and oxidizing acids, stress corrosion, and pitting corrosion. This makes it suitable for harsh chemical environments, such as those found in the petrochemical industry. It is particularly useful for components like pump shafts and turbine blades that must endure exposure to aggressive chemicals without degrading.
Incoloy 800 is a high-performance nickel-iron-chromium alloy designed for use in high-temperature and corrosive environments. The typical chemical composition of Incoloy 800 includes 30.0-35.0% nickel, 19.0-23.0% chromium, and the balance being iron. Additional elements include up to 0.10% carbon, up to 1.50% manganese, up to 1.00% silicon, up to 0.75% copper, 0.15-0.60% titanium, 0.15-0.60% aluminum, up to 0.045% phosphorus, and up to 0.015% sulfur. The high nickel and chromium content make the alloy highly resistant to oxidation and carburization. The presence of titanium and aluminum further enhances its stability and strength at elevated temperatures.
Incoloy 840 is another nickel-iron-chromium alloy, tailored with additional elements for various industrial uses. The chemical composition of Incoloy 840 includes 18.0-22.0% nickel, 18.0-22.0% chromium, with the balance being iron. It also contains up to 0.08% carbon, up to 1.00% manganese, up to 1.00% silicon, 0.60% copper, 0.60% titanium, 0.60% aluminum, up to 0.03% phosphorus, and up to 0.015% sulfur. This composition is designed to provide good strength and resistance to oxidizing and reducing acids. The lower nickel content compared to Incoloy 800 makes it more economical while still offering robust performance in moderate-temperature environments.
Both Incoloy 800 and Incoloy 840 are nickel-iron-chromium alloys, but their specific compositions cater to different industrial needs. Incoloy 800, with its higher nickel content (30.0-35.0%), offers superior resistance to oxidation and carburization, making it ideal for high-temperature applications. In contrast, Incoloy 840, with 18.0-22.0% nickel, is designed to be more cost-effective while still providing good performance in less demanding environments.
Both alloys have similar chromium content (18.0-23.0%), which contributes to their excellent resistance to oxidation. However, Incoloy 840 includes higher levels of copper, titanium, and aluminum, enhancing its strength and making it suitable for applications requiring robust mechanical properties at moderate temperatures. Additionally, Incoloy 840 has lower manganese (1.00% max) and phosphorus (0.03% max) compared to Incoloy 800 (1.50% max for Mn, 0.045% max for P), which also influences its performance characteristics.
Understanding these differences is crucial for selecting the appropriate alloy for specific industrial applications, ensuring optimal performance and longevity.
Understanding the mechanical properties of materials is crucial for selecting the right one for specific applications. Two important properties to consider are tensile strength and yield strength. Tensile strength refers to the maximum stress a material can withstand while being stretched or pulled before breaking. Yield strength, on the other hand, indicates the stress at which a material begins to deform permanently.
Incoloy 800 exhibits a tensile strength of approximately 86.5 ksi (596 MPa) and a yield strength of about 39.9 ksi (275 MPa). These strengths make it suitable for applications requiring moderate strength and good formability. In contrast, Incoloy 840 offers a tensile strength ranging from 83 ksi (572 MPa) to 130 ksi, with a yield strength between 35 ksi (241 MPa) and 320 MPa, depending on its treatment. This range allows Incoloy 840 to be tailored for applications needing higher strength.
Elongation measures how much a material can stretch before it breaks, reflecting its ductility. Both Incoloy 800 and Incoloy 840 exhibit good ductility, essential for forming and shaping processes. Incoloy 800 offers remarkable flexibility and versatility, with an elongation range of 30% to 45%. Meanwhile, Incoloy 840 shows an elongation range of 30% to 40%, providing sufficient ductility for many engineering applications.
High-temperature properties are vital for materials used in elevated temperature environments. Incoloy 800 maintains its mechanical integrity up to about 1500°F (816°C), making it ideal for heat exchangers and furnace components, where high creep and rupture strength are essential. In comparison, Incoloy 840 is typically used in applications with temperatures up to 1000°F (538°C), offering adequate performance where moderate temperature resistance is needed.
Incoloy 800 excels in resisting oxidation and stress corrosion, making it perfect for harsh environments. Its high chromium content is particularly beneficial in oxidizing conditions. Incoloy 840, while not as robust in acidic conditions, still offers significant resistance to stress and pitting corrosion, making it suitable for specific industrial applications where these properties are essential.
This analysis explores the cost differences, availability, and performance trade-offs between Incoloy 800 and Incoloy 840.
Incoloy 800 generally costs less due to its lower nickel content, while Incoloy 840, with a higher nickel content, tends to be pricier. Specifically, the alloy surcharge for Incoloy 800 ranges between $3.28 and $3.41, whereas Incoloy 840’s surcharge is slightly lower, ranging from $2.52 to $2.60. These figures can fluctuate with market conditions but provide a general understanding of the relative pricing.
Both Incoloy 800 and Incoloy 840 are widely available from various suppliers globally. Major manufacturers such as Special Metals ensure these alloys are accessible for different industrial applications. Their availability is relatively uniform across regions, making both alloys readily obtainable for manufacturing and engineering needs.
When selecting between Incoloy 800 and Incoloy 840, consider the performance versus cost tradeoff:
Incoloy 800 and Incoloy 840 have distinct applications based on their properties:
Ultimately, selecting between Incoloy 800 and 840 depends on balancing cost with performance needs, ensuring the best fit for your project’s demands.
Incoloy 800 meets important industry standards, making it ideal for high-temperature and corrosive settings.
Incoloy 800 conforms to ASTM B407 and ASME SB 407, which provide guidelines for its manufacturing, testing, and material properties. These standards cover seamless nickel-iron-chromium alloy pipes and tubes, ensuring that Incoloy 800 meets stringent requirements for quality and performance.
Incoloy 800 undergoes specific tests to meet ASTM and ASME standards:
Incoloy 840, although not as extensively standardized as Incoloy 800, still meets various industry requirements through its chemical and mechanical properties.
Incoloy 840 is often designated as S33400, with its composition falling within specific ranges for elements like chromium, nickel, and copper. While it does not have detailed ASTM or ASME standards, its compliance is generally verified through its adherence to specified chemical compositions and mechanical properties.
Rigorous mechanical testing confirms Incoloy 840’s suitability for high-strength applications:
Understanding these compliance aspects helps in selecting the appropriate alloy for various industrial applications, ensuring that the chosen material meets the necessary performance and safety standards.
In power generation, Incoloy 800 is frequently employed due to its high temperature resistance and corrosion protection. For example, steam generators and heat exchangers in power plants benefit from Incoloy 800’s ability to withstand temperatures up to 1100°F (593°C) without significant degradation. This alloy’s resistance to oxidation (a reaction where materials react with oxygen) and carburization (the absorption of carbon into a material) ensures the longevity and efficiency of components, making it a preferred choice in high-temperature environments.
In chemical processing plants, Incoloy 840 is highly valued for its resistance to reducing and oxidizing acids. This makes it ideal for components exposed to harsh chemical environments. For instance, in the production of fertilizers, Incoloy 840’s ability to resist pitting corrosion and stress corrosion cracking is essential. Imagine a scenario where a pump shaft continuously handles aggressive chemicals; the durability of Incoloy 840 ensures that such components remain reliable over long periods, minimizing downtime and maintenance costs.
In aerospace and turbines, Incoloy 840’s higher strength offers key advantages. Components like turbine blades must endure high stresses and temperatures. Incoloy 840’s higher yield strength (320 MPa) ensures that it can handle these demanding conditions, contributing to the reliability and performance of critical aerospace and turbine components.
Incoloy 800 is often preferred in applications involving high temperatures, such as heat exchangers and pressure vessels. Its excellent resistance to oxidation and carburization up to 1100°F (593°C) makes it suitable for high-temperature environments. Here’s a comparison to illustrate the differences in high-temperature performance:
Incoloy 800:
Maximum Temperature: 1100°F (593°C)
Melting Point: 2475-2525°F (1357-1385°C)
Ideal for: Heat exchangers, pressure vessels
Incoloy 840:
Maximum Temperature: Slightly lower than Incoloy 800
Melting Point: Not specified but generally lower than Incoloy 800
Ideal for: Components requiring higher mechanical strength in moderate temperatures
Incoloy 840, with its composition including chromium, nickel, and molybdenum, is ideal for petrochemical applications where resistance to reducing and oxidizing acids, stress corrosion cracking, and pitting corrosion is crucial. This alloy is commonly used in components like pump shafts and turbine blades that must withstand harsh chemicals over extended periods. Its ability to perform well in these environments ensures that petrochemical processing equipment remains durable and efficient.
In summary, both Incoloy 800 and Incoloy 840 offer distinct benefits tailored to specific industrial needs. Incoloy 800 excels in high-temperature environments, making it ideal for power generation and heat exchangers. Meanwhile, Incoloy 840’s superior mechanical strength and chemical resistance make it a prime choice for chemical processing and aerospace applications. Understanding these unique properties can help industry professionals select the most suitable alloy for their specific requirements, ensuring optimal performance and longevity of their equipment.
Below are answers to some frequently asked questions:
The key differences in chemical composition between Incoloy 800 and Incoloy 840 are primarily in their carbon, manganese, phosphorus, chromium, nickel, and titanium/aluminum content. Incoloy 800 has higher carbon (0.10% max), manganese (up to 1.50%), and nickel (30.0-35.0%) content compared to Incoloy 840, which has lower carbon (0.08% max), manganese (up to 1.00%), and nickel (18.0-22.0%) content. Additionally, Incoloy 840 includes copper, enhancing its strength but increasing susceptibility to acidic corrosion. These variations impact their mechanical properties and suitability for different applications, with Incoloy 800 being preferred for high-temperature environments and Incoloy 840 for its resistance to specific acids.
Incoloy 800 generally offers better overall mechanical properties compared to Incoloy 840. It has a higher yield strength (around 275 MPa versus 241 MPa for Incoloy 840), better ductility with an elongation of approximately 45% compared to 40% for Incoloy 840, and superior high-temperature performance, being usable up to 1100°F (593°C) versus 1000°F (538°C) for Incoloy 840. While Incoloy 840 has higher tensile strength in some contexts, Incoloy 800’s combination of mechanical strength, ductility, and high-temperature resilience typically makes it the better choice for many applications.
Incoloy 800 is typically used in the chemical, marine, oil and gas, and power generation industries due to its excellent corrosion resistance, high-temperature strength, and ability to withstand carburization and oxidation. It is ideal for furnace components, superheaters, and nuclear steam generating tubes. Incoloy 840, on the other hand, is favored in the petrochemical industry, high-strength applications such as gas turbines and exhaust systems, and general industrial use where durability in harsh conditions and superior tensile strength are required. Each alloy is chosen based on specific application needs, with Incoloy 800 preferred for higher temperature limits and corrosion resistance, and Incoloy 840 for its higher mechanical strength.
Incoloy 800 generally has a broader price range, with seamless pipes costing between $1000 to $4000 per ton and welded pipes ranging from $7.6 to $50 per kilogram. Incoloy 840 lacks specific pricing data but typically has a lower surcharge, around $2.60 per unit compared to $3.41 for Incoloy 800, suggesting it might be slightly cheaper or comparable in cost. Ultimately, prices depend on factors like supplier, material form, and application requirements, with Incoloy 840 potentially offering competitive pricing due to its unique properties and lower surcharge.
Incoloy 800 and Incoloy 840 comply with industry standards through adherence to specific chemical compositions, heat treatment protocols, and rigorous testing requirements. Incoloy 800, defined by UNS N08800, conforms to ASTM B407 and ASME SB 407 standards, ensuring it meets criteria for high-temperature applications with excellent resistance to oxidation and carburization. Incoloy 840, although not associated with a specific UNS number, undergoes similar testing to ensure its mechanical properties and corrosion resistance meet industry requirements for applications like gas turbines and petrochemical environments. These standards ensure both alloys perform reliably in their respective industrial uses.
Incoloy 800 is known for its superior corrosion resistance, particularly in high-temperature environments and against a variety of corrosive media, such as molten salts and sulphuric acid. It can withstand temperatures up to 1100°F (593°C) and is resistant to stress-corrosion cracking, including chloride stress corrosion. In contrast, Incoloy 840, while offering good resistance to reducing and oxidizing acids and stress corrosion, is limited to 1000°F (538°C) and is slightly more susceptible to acidic corrosion due to its copper content. Thus, Incoloy 800 is generally better for extreme conditions, while Incoloy 840 suits petrochemical applications.
