Hastelloy C-22
About Hastelloy C-22
Name and Equivalent Name: Hastelloy C-22, Alloy C-22, or Nicrofer 5923, corresponds to UNS N06022. It complies with ASTM B575, B619, B622, DIN/EN 2.4602, GB/T 14992: NS331, AMS 5837, and ASME SB-575. This alloy is certified under ISO 15156 and NACE MR0175, ensuring reliability in highly corrosive and high-temperature environments.
Hastelloy C-22 Basic Introduction
Hastelloy C-22 is a nickel-based superalloy known for its exceptional resistance to oxidizing and reducing agents, including chlorides, sulfuric acid, and ferric ions. It is widely used in chemical reactors, heat exchangers, and gas scrubbers, where exposure to aggressive chemicals occurs daily.
With high mechanical strength and excellent thermal fatigue resistance, Hastelloy C-22 performs well under extreme conditions. The alloy maintains stability in temperatures up to 980°C, making it ideal for applications that involve both chemical exposure and temperature cycling, such as energy, power generation, and chemical processing industries.
Alternative Superalloys of Hastelloy C-22
Alternatives to Hastelloy C-22 include Hastelloy C-276, Inconel 625, Alloy 20, and Monel 400. Hastelloy C-276 provides enhanced corrosion resistance in oxidizing and reducing environments, while Inconel 625 offers superior mechanical strength under extreme heat. Alloy 20 is preferred for sulfuric acid applications, and Monel 400 is ideal for marine environments due to its seawater resistance. Each alloy serves specific needs based on the operational environment.
Hastelloy C-22 Design Intention
Hastelloy C-22 was designed for environments requiring resistance to both oxidizing and reducing chemicals. Its high molybdenum content ensures resistance to pitting and crevice corrosion, while chromium enhances performance in oxidizing agents. The alloy also provides excellent resistance to stress corrosion cracking and thermal cycling.
With its ability to perform at elevated temperatures and high resistance to chemical degradation, Hastelloy C-22 is a reliable choice for applications that demand chemical stability and mechanical integrity. It ensures long service life and reduces maintenance in reactors, heat exchangers, and gas scrubbers.
Hastelloy C-22 Chemical Composition
Hastelloy C-22 contains key elements such as molybdenum and chromium to enhance corrosion resistance in aggressive environments. Adding tungsten improves the alloy's strength and stability at high temperatures.
Element | Content (wt%) |
|---|---|
Nickel (Ni) | Balance |
Chromium (Cr) | 20.0 - 22.5 |
Molybdenum (Mo) | 12.5 - 14.5 |
Iron (Fe) | 2.0 - 6.0 |
Tungsten (W) | 2.5 - 3.5 |
Carbon (C) | Max 0.015 |
Silicon (Si) | Max 0.08 |
Hastelloy C-22 Physical Properties
Hastelloy C-22 exhibits high density, excellent thermal conductivity, and outstanding thermal fatigue resistance, enabling it to perform reliably in chemically harsh environments.
Property | Value |
|---|---|
Density (g/cm³) | 8.69 |
Melting Point (°C) | 1355 |
Thermal Conductivity (W/(m·K)) | 9.2 |
Modulus of Elasticity (GPa) | 206 |
Metallographic Structure of Hastelloy C-22 Superalloy
Hastelloy C-22 features a face-centered cubic (FCC) microstructure, typical of nickel-based alloys, which enhances its ductility and toughness. The alloy is resistant to the formation of intermetallic phases, ensuring consistent mechanical properties under prolonged exposure to high temperatures.
The alloy's careful balance of chromium, molybdenum, and tungsten prevents pitting and stress corrosion cracking. Additionally, its metallurgical stability ensures resistance to localized corrosion, even in environments with fluctuating temperatures and chemical compositions.
Hastelloy C-22 Mechanical Properties
Hastelloy C-22 combines excellent mechanical strength with superior thermal fatigue resistance, providing long-term durability in demanding environments.
Mechanical Property | Value |
|---|---|
Tensile Strength (MPa) | 760 - 780 |
Yield Strength (MPa) | 350 - 450 |
Creep Strength (Temperature) | Effective at 980°C |
Fracture Toughness | High |
Fatigue Strength | High resistance to thermal cycling |
Creep Rupture Life | Long-lasting at 600°C |
Hardness (HRC) | Rockwell C20 - 30 |
Elongation (%) | ~45 |
Elastic Modulus (GPa) | ~210 |
Key Features of Hastelloy C-22 Superalloy
1. Exceptional Corrosion Resistance
Hastelloy C-22 offers superior resistance to oxidizing and reducing chemicals, including chlorides and acids, ensuring reliable performance in aggressive environments.
2. Thermal Fatigue Resistance
The alloy performs effectively under thermal cycling, resisting fatigue and ensuring mechanical integrity in fluctuating temperatures.
3. High-Temperature Stability
With strong creep performance and mechanical stability at temperatures up to 980°C, Hastelloy C-22 is ideal for high-temperature reactors and heat exchangers.
4. Pitting and Crevice Corrosion Resistance
The high molybdenum content ensures excellent resistance to pitting and crevice corrosion, extending the lifespan of components in chemical processing.
5. Versatile Applications Across Industries
Hastelloy C-22 is widely used in chemical processing, energy, aerospace, and marine industries due to its ability to withstand extreme conditions and aggressive chemicals.
Hastelloy C-22 Superalloy’s Machinability
Vacuum Investment Casting: Hastelloy C-22 is not ideal for Vacuum Investment Casting due to its high molybdenum content, which can hinder fluidity and cause casting defects. Alloys with better flow characteristics are preferred for precision casting.
Single Crystal Casting: Hastelloy C-22 is not used in Single Crystal Casting because it lacks the structural characteristics needed to form single crystals, which are essential for high-stress turbine applications.
Equiaxed Crystal Casting: Hastelloy C-22 can be used in Equiaxed Crystal casting, but its primary focus on corrosion resistance limits its use in applications demanding high mechanical strength, like turbine blades.
Directional Casting: The alloy is unsuitable for Superalloy Directional Casting as it lacks the creep and fatigue resistance required for directional solidified components used in aerospace.
Powder Metallurgy Turbine Disc: Hastelloy C-22 is typically employed in Powder Metallurgy Turbine Disc applications of Superior oxidation and corrosion resistance.
Precision Forging: Hastelloy C-22 is suitable for Superalloy Precision Forging, producing durable components with excellent corrosion resistance for chemical processing and energy industries.
Superalloy 3D Printing: Superalloy 3D Printing allows the production of intricate Hastelloy C-22 parts with excellent corrosion resistance, primarily for chemical and pharmaceutical equipment.
CNC Machining: CNC Machining is feasible with Hastelloy C-22, though it requires advanced tools and techniques to handle the alloy's work-hardening nature and maintain precision.
Superalloy Welding: Superalloy Welding with Hastelloy C-22 is effective due to the alloy's low carbon content, which minimizes carbide precipitation, ensuring reliable welds.
Hot Isostatic Pressing (HIP): Hot Isostatic Pressing (HIP) enhances Hastelloy C-22's structural integrity by eliminating porosity and improving performance under high-pressure, high-temperature conditions.
Hastelloy C-22 Superalloy Applications
Aerospace and Aviation: Hastelloy C-22 is used in Aerospace and Aviation for auxiliary components exposed to corrosive chemicals and high temperatures, such as exhaust systems and gas scrubbers.
Power Generation: In Power Generation, Hastelloy C-22 is utilized for heat exchangers and gas scrubbers operating under chemically aggressive conditions.
Oil and Gas: The alloy is essential in Oil and Gas applications, providing long-lasting resistance to hydrogen sulfide and harsh chemicals in pipelines and valves.
Energy: Hastelloy C-22 plays a key role in Energy operations, including reactors and chemical storage, ensuring safety and reliability in high-temperature environments.
Marine: In Marine environments, the alloy’s corrosion resistance makes it ideal for desalination systems and chemical-handling equipment in saltwater conditions.
Mining: Hastelloy C-22 is used in Mining for equipment exposed to corrosive chemicals, ensuring reliable performance in extraction processes.
Automotive: In Automotive applications, Hastelloy C-22 is employed in specialized exhaust systems and chemical-handling components in electric vehicles.
Chemical Processing: Hastelloy C-22 is essential in Chemical Processing for reactors, heat exchangers, and other equipment exposed to aggressive chemicals and fluctuating temperatures.
Pharmaceutical and Food: In the Pharmaceutical and Food industries, Hastelloy C-22 ensures equipment remains uncontaminated and corrosion-free, meeting hygiene standards.
Military and Defense: Hastelloy C-22 is used in Military and Defense for storage tanks and equipment handling corrosive substances, ensuring durability under extreme conditions.
Nuclear: The alloy is applied in Nuclear reactors and cooling systems, offering long-term stability and corrosion resistance under high temperatures and pressure.
When to Choose Hastelloy C-22 Superalloy
Custom superalloy parts made from Hastelloy C-22 are essential for environments where both chemical resistance and thermal stability are critical. Its ability to withstand oxidizing and reducing agents makes it a preferred material for reactors, heat exchangers, and gas scrubbers in chemical and power generation industries.
Hastelloy C-22 should be selected when the operating conditions involve fluctuating temperatures and aggressive chemicals. Its corrosion resistance and high mechanical strength ensure long service life and minimal maintenance. Additionally, the alloy’s compatibility with HIP, welding, and precision forging makes it suitable for applications requiring robust and durable components. Choose Hastelloy C-22 for operations demanding the highest level of reliability in harsh environments.
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