Hastelloy B-2
About Hastelloy B-2
Name and Equivalent Name: Hastelloy B-2, or Alloy B-2 or UNS N10665, is widely recognized for its superior corrosion resistance in reducing environments. It complies with standards such as ASTM B333, B335, B366, DIN/EN 2.4617, BS 3072: NA54, GB/T 14992: NS143B, and AMS 5537. Additionally, it is listed in ASME SB-366, ISO 15156, and NACE MR0175.
Hastelloy B-2 Basic Introduction
Hastelloy B-2 is a corrosion-resistant nickel-molybdenum alloy designed to excel in highly acidic environments, particularly hydrochloric acid. It prevents stress corrosion cracking, pitting, and crevice corrosion, making it ideal for chemical processes.
This alloy retains high mechanical strength under thermal stress and is resistant to thermal fatigue. With strong creep performance at elevated temperatures, Hastelloy B-2 ensures the durability of reactors, heat exchangers, and other equipment in aggressive environments where performance and longevity are critical.
Alternative Superalloys of Hastelloy B-2
Alternative materials to Hastelloy B-2 include Hastelloy C276, Inconel 625, Monel 400, and Alloy 20. These alloys offer corrosion resistance but with distinct capabilities in various environments.
Hastelloy C276 performs better in oxidizing environments, while Inconel 625 provides higher oxidation resistance at elevated temperatures. Monel 400 is excellent for marine applications, and Alloy 20 offers superior resistance to sulfuric acid. Selection depends on the specific operating conditions.
Hastelloy B-2 Design Intention
Hastelloy B-2 was developed to withstand highly corrosive environments, especially those with hydrochloric acid while preventing localized corrosion and stress cracking. This ensures safer and longer-lasting chemical processing equipment.
The alloy maintains mechanical integrity under continuous exposure to high temperatures, making it ideal for reactors and heat exchangers. With resistance to thermal fatigue, Hastelloy B-2 is suitable for operations involving temperature fluctuations and mechanical stress over extended periods.
Hastelloy B-2 Chemical Composition
Hastelloy B-2's composition is tailored to resist stress corrosion cracking and pitting in reducing environments. Molybdenum enhances corrosion resistance, while controlled iron content prevents embrittlement.
Element | Content (wt%) |
|---|---|
Nickel (Ni) | Balance |
Chromium (Cr) | 1.0 max |
Molybdenum (Mo) | 26.0 - 30.0 |
Iron (Fe) | 2.0 max |
Carbon (C) | Max 0.02 |
Silicon (Si) | Max 0.1 |
Hastelloy B-2 Physical Properties
Hastelloy B-2 offers a high density, excellent thermal conductivity, and mechanical strength. These properties make it suitable for corrosive environments requiring thermal stability and mechanical reliability.
Property | Value |
|---|---|
Density (g/cm³) | 9.24 |
Melting Point (°C) | 1370 |
Thermal Conductivity (W/(m·K)) | 10.2 |
Modulus of Elasticity (GPa) | 205 |
Metallographic Structure of Hastelloy B-2 Superalloy
Hastelloy B-2 exhibits a face-centered cubic (FCC) crystal structure typical of nickel-based alloys. The absence of chromium-rich phases ensures the alloy retains its corrosion resistance in reducing environments without becoming brittle.
With minimal intermetallic phase formation during heat treatment, the alloy provides excellent thermal stability. Its molybdenum content enhances resistance to pitting and crevice corrosion, ensuring that components remain durable even under prolonged exposure to harsh chemicals and high temperatures.
Hastelloy B-2 Mechanical Properties
Hastelloy B-2 offers high strength and reliable creep resistance, making it ideal for applications involving continuous thermal stress. Its fatigue and fracture toughness ensure durability in fluctuating environments.
Mechanical Property | Value |
|---|---|
Tensile Strength (MPa) | 690 - 760 |
Yield Strength (MPa) | 250 - 300 |
Creep Strength (800°C) | Strong |
Fracture Toughness | High |
Fatigue Strength | Strong in reducing environments |
Creep Rupture Life (600°C) | >20,000 hours |
Hardness (HRC) | Rockwell B90 - 95 |
Elongation (%) | ~40 |
Elastic Modulus (GPa) | ~205 |
Key Features of Hastelloy B-2 Superalloy
1. Exceptional Corrosion Resistance
Hastelloy B-2 provides outstanding resistance to hydrochloric acid and other reducing agents. It is resistant to pitting, crevice corrosion, and stress corrosion cracking, ensuring the durability of components in aggressive environments.
2. High Thermal Stability
With a melting point of 1370°C and strong performance at temperatures up to 800°C, Hastelloy B-2 maintains mechanical integrity under extreme conditions, making it ideal for reactors and heat exchangers.
3. Long Creep Rupture Life
Hastelloy B-2 offers over 20,000 hours of creep rupture life at 600°C, ensuring reliability for equipment operating under constant stress and temperature fluctuations.
4. Strong Mechanical Properties
The alloy demonstrates excellent tensile strength (690–760 MPa) and fracture toughness, ensuring it withstands mechanical stress while maintaining flexibility with a 40% elongation rate.
5. Enhanced Fatigue Resistance
Hastelloy B-2 resists thermal fatigue, making it suitable for operations with temperature fluctuations. This feature ensures long-lasting performance in reactors, pumps, and valves used in chemical processing.
Hastelloy B-2 Superalloy’s Machinability
Vacuum Investment Casting: Hastelloy B-2 is not suitable for Vacuum Investment Casting due to its limited flowability and high molybdenum content, which increases the risk of cracking during casting. Alloys with better casting properties are preferred for such applications.
Single Crystal Casting: Hastelloy B-2 is not typically used in Single Crystal Casting as it lacks the specific metallurgical characteristics required to form single crystals. This process demands alloys optimized for high creep resistance in turbine components.
Equiaxed Crystal Casting: Hastelloy B-2 can be applied in Equiaxed Crystal Casting but is not widely used, as its focus is on corrosion resistance rather than the mechanical strength needed for high-stress turbine applications.
Directional Casting: Hastelloy B-2 is unsuitable for Superalloy Directional Casting due to its lack of the necessary mechanical properties required for components subjected to directional solidification and high thermal stress.
Powder Metallurgy Turbine Disc: Hastelloy B-2 is not a common choice for Powder Metallurgy Turbine Disc manufacturing, as the alloy's primary benefit is corrosion resistance rather than the mechanical strength required for turbine applications.
Precision Forging: Hastelloy B-2 is suitable for Superalloy Precision Forging due to its corrosion resistance and good mechanical properties at elevated temperatures, making it valuable for chemical processing equipment and reactors.
Superalloy 3D Printing: Superalloy 3D Printing with Hastelloy B-2 is feasible, allowing complex designs with excellent corrosion resistance. It is beneficial for producing intricate parts for the chemical and pharmaceutical industries.
CNC Machining: Hastelloy B-2 performs well in CNC Machining with appropriate tooling and cooling strategies. Its tendency to work harden requires specialized equipment for machining precise chemical and industrial components.
Superalloy Welding: Superalloy Welding with Hastelloy B-2 is possible, provided proper techniques are used to minimize cracking. Post-weld heat treatments improve joint performance in corrosive environments.
Hot Isostatic Pressing (HIP): Hot Isostatic Pressing (HIP) enhances the properties of Hastelloy B-2 by eliminating porosity and improving strength, making it suitable for critical chemical and industrial applications.
Hastelloy B-2 Superalloy Applications
Aerospace and Aviation: Hastelloy B-2 is used in Aerospace and Aviation for auxiliary components like fuel system parts that require high corrosion resistance in chemical environments.
Power Generation: In Power Generation, Hastelloy B-2 is utilized for heat exchangers and condensers that operate in acidic or corrosive cooling systems, ensuring long service life.
Oil and Gas: The alloy plays a crucial role in Oil and Gas applications, such as in pipelines and valves exposed to hydrogen sulfide and acidic environments, providing reliability under extreme conditions.
Energy: In the Energy sector, Hastelloy B-2 is used in chemical storage tanks and reactors that encounter high temperatures and corrosive fluids, maintaining integrity over time.
Marine: Hastelloy B-2 ensures durability in Marine environments by resisting seawater corrosion, making it suitable for desalination plants and other marine chemical handling equipment.
Mining: In Mining, Hastelloy B-2 is applied in equipment handling corrosive chemicals, such as slurry pipelines, contributing to efficient mineral extraction.
Automotive: Though not widely used in Automotive, Hastelloy B-2 may be found in exhaust systems and chemical handling parts in electric vehicles, where corrosion resistance is essential.
Chemical Processing: Hastelloy B-2 is preferred in Chemical Processing industries due to its exceptional resistance to hydrochloric acid, ensuring long-term reliability in reactors and heat exchangers.
Pharmaceutical and Food: In the Pharmaceutical and Food industries, the alloy's corrosion resistance ensures safety and hygiene in processing equipment exposed to aggressive cleaning chemicals.
Military and Defense: Hastelloy B-2 is valuable in Military and Defense applications, such as chemical storage systems, providing durability in harsh environments.
Nuclear: The alloy is used in Nuclear environments for equipment handling corrosive fluids, ensuring long-lasting performance in cooling systems and chemical reactors.
When to Choose Hastelloy B-2 Superalloy
Custom superalloy parts made from Hastelloy B-2 are ideal when dealing with highly corrosive chemical environments, particularly those involving hydrochloric acid. The alloy’s exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking makes it a reliable choice for reactors, heat exchangers, and chemical storage tanks.
Hastelloy B-2 is suitable when long-term performance under thermal stress is required. It ensures high mechanical strength and stability at elevated temperatures, making it valuable in chemical processing, energy, and pharmaceuticals. Additionally, its compatibility with advanced manufacturing techniques such as precision forging, HIP, and 3D printing further extends its application range. This alloy is a smart choice when equipment must maintain durability and integrity under severe chemical and environmental conditions.
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