Hastelloy C-276
About Hastelloy C-276
Name and Equivalent Name: Hastelloy C-276, also known as UNS N10276, is a high-performance alloy widely used in aggressive chemical environments. It is recognized under ASTM B575, B619, and B622, DIN/EN 2.4819, GB/T 14992: NS334, AMS 5775, ASME SB-575, ISO 15156, and NACE MR0175 standards. It is also known as Nicrofer 5716 or Alloy C-276.
Hastelloy C-276 Basic Introduction
Hastelloy C-276 is a nickel-molybdenum-chromium alloy known for its superior resistance to strong oxidizing and reducing agents. It offers excellent corrosion resistance in acidic and alkaline environments, including sulfuric, hydrochloric, and phosphoric acids.
The alloy is highly resistant to pitting, crevice corrosion, and stress corrosion cracking, ensuring reliability in harsh industrial environments. With high thermal fatigue resistance, it maintains mechanical strength at elevated temperatures, making it ideal for chemical processing, power generation, and marine applications.
Alternative Superalloys of Hastelloy C-276
Alternatives to Hastelloy C-276 include Hastelloy C-22, which offers improved resistance to oxidizing agents, and Inconel 625, which is known for superior mechanical properties at elevated temperatures. Alloy 20 performs well in sulfuric acid environments, while Monel 400 is better suited for marine applications with its resistance to seawater corrosion. Each alloy caters to specific environmental challenges.
Hastelloy C-276 Design Intention
Hastelloy C-276 was designed for environments exposed to aggressive chemicals and fluctuating temperatures. The alloy aims to provide both corrosion resistance and mechanical durability. Its molybdenum content ensures resistance to pitting, while chromium enhances oxidation resistance.
The alloy’s high thermal stability allows it to maintain strength between 650°C and 850°C, making it effective in chemical reactors, heat exchangers, and gas scrubbers. Additionally, its resistance to intergranular corrosion ensures longevity, even after welding or exposure to high temperatures.
Hastelloy C-276 Chemical Composition
Hastelloy C-276 contains elements that ensure superior resistance to corrosion, mechanical stability, and thermal durability.
Element | Content (wt%) |
|---|---|
Nickel (Ni) | Balance |
Chromium (Cr) | 14.5 - 16.5 |
Molybdenum (Mo) | 15.0 - 17.0 |
Iron (Fe) | 4.0 - 7.0 |
Tungsten (W) | 3.0 - 4.5 |
Carbon (C) | Max 0.01 |
Silicon (Si) | Max 0.08 |
Hastelloy C-276 Physical Properties
Hastelloy C-276’s physical properties ensure reliability under high temperatures and corrosive conditions, making it suitable for demanding industrial environments.
Property | Value |
|---|---|
Density (g/cm³) | 8.89 |
Melting Point (°C) | 1335 |
Thermal Conductivity (W/(m·K)) | 10.2 |
Modulus of Elasticity (GPa) | 205 |
Metallographic Structure of Hastelloy C-276 Superalloy
Hastelloy C-276 features a face-centered cubic (FCC) structure, enhancing its toughness and corrosion resistance. This microstructure ensures minimal phase separation and prevents carbide precipitation during welding, preserving the alloy’s mechanical properties.
The alloy’s balanced chemical composition ensures uniform performance under varying temperatures and chemical exposures. Its metallurgical stability reduces the formation of brittle phases, maintaining structural integrity even after prolonged exposure to harsh environments.
Hastelloy C-276 Mechanical Properties
Hastelloy C-276 offers excellent mechanical strength, thermal fatigue resistance, and durability in aggressive environments, ensuring reliable performance in critical applications.
Mechanical Property | Value |
|---|---|
Tensile Strength (MPa) | 760 - 800 |
Yield Strength (MPa) | 350 - 450 |
Creep Strength | Strong at 650-850°C |
Fracture Toughness | High |
Fatigue Strength | High for harsh environments |
Thermal Fatigue Resistance | High |
Creep Rupture Life | Long service life at elevated temperatures |
Hardness (HRC) | Rockwell C20 - 35 |
Elongation (%) | ~50 |
Elastic Modulus (GPa) | ~210 |
Key Features of Hastelloy C-276 Superalloy
1. Exceptional Corrosion Resistance
Hastelloy C-276 provides outstanding resistance to various chemicals, including strong acids and chlorine-containing environments. Its resistance to pitting, crevice corrosion, and stress corrosion cracking ensures reliability in aggressive chemical processes.
2. Thermal Fatigue Resistance
With high thermal stability, the alloy performs well under fluctuating temperatures, maintaining mechanical integrity and minimizing thermal fatigue failures.
3. High-Temperature Strength
Hastelloy C-276 retains its mechanical properties at 650°C and 850°C, making it suitable for high-temperature reactors and heat exchangers.
4. Weldability and Structural Integrity
The alloy’s low carbon content prevents carbide precipitation during welding, ensuring structural stability and minimizing the risk of intergranular corrosion.
5. Long Service Life in Harsh Environments
Hastelloy C-276 is designed to provide extended durability in environments exposed to extreme chemical and thermal conditions, reducing maintenance and operational downtime.
Hastelloy C-276 Superalloy’s Machinability
Vacuum Investment Casting: Hastelloy C-276 is not ideal for Vacuum Investment Casting due to its tendency to form surface defects and limited fluidity. Precision casting techniques favor alloys with higher castability for complex parts.
Single Crystal Casting: Hastelloy C-276 cannot be used for Single Crystal Casting since it lacks the specific microstructural properties required to produce single-crystal components, such as turbine blades.
Equiaxed Crystal Casting: While feasible for Equiaxed Crystal Casting, Hastelloy C-276's primary strength lies in corrosion resistance, limiting its use in high-strength structural components.
Directional Casting: Hastelloy C-276 is unsuitable for Superalloy Directional Casting due to the required creep resistance and grain orientation for turbine components.
Powder Metallurgy Turbine Disc: The alloy’s properties make it unsuitable for Powder Metallurgy Turbine Disc production, where high mechanical endurance under stress is paramount.
Precision Forging: Hastelloy C-276 can be effectively used in Superalloy Precision Forging to create components with superior corrosion resistance for chemical and energy applications.
Superalloy 3D Printing: Superalloy 3D Printing is feasible with Hastelloy C-276, producing complex shapes with excellent corrosion resistance for chemical and pharmaceutical industries.
CNC Machining: CNC Machining is effective with Hastelloy C-276, though advanced tooling is needed to manage its work-hardening behavior and maintain precision.
Superalloy Welding: Superalloy Welding with Hastelloy C-276 is reliable, as its low carbon content prevents carbide precipitation, ensuring solid and corrosion-resistant joints.
Hot Isostatic Pressing (HIP): Hot Isostatic Pressing (HIP) enhances Hastelloy C-276's mechanical properties by reducing porosity, making it ideal for high-pressure applications.
Hastelloy C-276 Superalloy Applications
Aerospace and Aviation: Hastelloy C-276 is used in Aerospace and Aviation for exhaust systems and chemical handling equipment, providing corrosion resistance in harsh environments.
Power Generation: In Power Generation, Hastelloy C-276 is employed in heat exchangers and gas scrubbers, offering reliability under extreme chemical exposure and temperature fluctuations.
Oil and Gas: Hastelloy C-276 is essential in Oil and Gas applications, protecting pipelines and valves from hydrogen sulfide and other corrosive agents.
Energy: The alloy plays a crucial role in Energy systems, providing corrosion resistance in reactors and storage tanks exposed to aggressive chemicals.
Marine: In Marine applications, Hastelloy C-276 ensures long-term resistance to seawater corrosion in desalination plants and offshore structures.
Mining: Hastelloy C-276 is used in Mining equipment exposed to chemically aggressive materials, providing corrosion resistance and durability.
Automotive: In Automotive industries, Hastelloy C-276 is utilized in exhaust systems and components exposed to high temperatures and corrosive gases.
Chemical Processing: The alloy is widely applied in Chemical Processing for reactors, heat exchangers, and other equipment exposed to aggressive chemicals.
Pharmaceutical and Food: Hastelloy C-276 ensures cleanliness and safety in Pharmaceutical and Food processing equipment, resisting aggressive cleaning agents.
Military and Defense: In Military and Defense applications, the alloy is used in chemical storage systems, offering durability under extreme environmental conditions.
Nuclear: Hastelloy C-276 is employed in Nuclear reactors and cooling systems, providing corrosion resistance under high temperatures and pressure.
When to Choose Hastelloy C-276 Superalloy
Custom superalloy parts made from Hastelloy C-276 are ideal when corrosion resistance and mechanical durability are required. Its ability to resist oxidizing and reducing agents makes it a preferred material for equipment exposed to aggressive chemicals and extreme temperatures.
Hastelloy C-276 should be selected for environments with high thermal fatigue or chemical exposure, such as reactors, heat exchangers, and gas scrubbers in power generation and chemical processing. Its low carbon content ensures excellent weldability, reducing the risk of intergranular corrosion. Hastelloy C-276 offers reliability and extended service life with minimal maintenance, whether for aerospace, marine, or nuclear applications.
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