Seamless Hastelloy B2 pipe
Our Hastelloy B2 seamless pipes are designed to resist the formation of grain-boundary carbide precipitates in the weld heat-affected zone, ensuring superior intergranular corrosion resistance in the as-welded condition. This alloy offers outstanding protection against pitting, stress-corrosion cracking (SCC), and sulfuric or phosphoric acids in reducing environments. Through advanced cold-drawing and vacuum annealing, GZH ensures every pipe maintains tight dimensional tolerances and a high-integrity surface finish for the most demanding chemical processing and petrochemical applications.
"For applications requiring enhanced thermal stability during fabrication, please also check our Hastelloy B3 solutions."
Seamless Hastelloy B2 Pipe (UNS N10665): Properties, Specifications, and Applications for Reducing Acid Environments
Introduction to Hastelloy B2
Hastelloy B2 (UNS N10665) is a high-performance nickel–molybdenum corrosion-resistant alloy specifically designed to withstand extremely reducing chemical environments. With its high molybdenum content and minimal chromium concentration, Hastelloy B2 offers exceptional resistance to hydrochloric acid and other non-oxidizing acids.
ASeamless Hastelloy B2 Pipe is manufactured from a solid billet using hot extrusion and precision cold drawing processes, eliminating welded seams that could become weak points in corrosive environments. This seamless construction ensures uniform metallurgical structure, consistent wall thickness, and enhanced mechanical reliability, making it ideal for high-pressure and high-vacuum chemical processing systems.
Hastelloy B2 remains one of the most trusted materials for industries handling concentrated hydrochloric acid, sulfuric acid catalysts, and other reducing chemical media.
Engineered for Strong Reducing Environments
The performance of Hastelloy B2 is largely derived from its high molybdenum content (26–30%), which significantly improves resistance to hydrochloric acid corrosion across a wide range of concentrations and temperatures.
In seamless pipe form, the absence of weld seams provides additional protection against selective corrosion attack and metallurgical discontinuities, which can occur in welded structures under aggressive chemical conditions.
As a result, seamless Hastelloy B2 pipes are widely used in chemical reactors, acid handling pipelines, and critical process equipment.
Key Features and Technical Advantages
Exceptional Resistance to Hydrochloric Acid
Hastelloy B2 demonstrates outstanding corrosion resistance in boiling hydrochloric acid at nearly all concentrations, making it one of the most effective alloys for HCl service.
It also performs well in other reducing acids, including:
- Phosphoric acid
- Sulfuric acid (in reducing conditions)
- Organic acids
Resistance to Chloride-Induced Stress Corrosion Cracking
The high nickel base of Hastelloy B2 provides excellent resistance to chloride-induced stress corrosion cracking (SCC), which commonly affects stainless steels in chloride environments.
Low Carbon Content for Enhanced Corrosion Resistance
The alloy's low carbon composition minimizes carbide precipitation at grain boundaries, helping maintain corrosion resistance in heat-affected zones during welding.
Stable Mechanical Performance
Hastelloy B2 maintains reliable mechanical properties from cryogenic temperatures up to approximately 800°C in non-oxidizing environments, supporting its use in demanding chemical processes.
Compliance with International Standards
Seamless Hastelloy B2 pipes are typically produced according to:
- ASTM B622 – Seamless Nickel and Nickel-Cobalt Alloy Pipe and Tube
- ASTM B829 – General Requirements for Nickel Alloy Pipe and Tube
Chemical Composition of Hastelloy B2 (UNS N10665)
The balanced composition of nickel and molybdenum provides the alloy’s superior corrosion resistance in reducing media.
Table 1: Chemical Composition of Hastelloy B2
The composition of Hastelloy B2 is carefully balanced to achieve its superior corrosion resistance and high strength.
| Grade | Ni | Cr | Mo | Fe | C | Si | Co | Mn | P | S |
| UNS N10665 | Balance | ≤1.00 | 26.00-30.00 | ≤2.00 | ≤0.02 | ≤0.10 | ≤1.00 | ≤1.00 | 0.04 | 0.03 |
Table 2: Typical Mechanical Properties of Hastelloy B2
Hastelloy B2 is specifically designed to maintain its strength and shape in high-stress, corrosive environments.
Tensile Strength | Yield Strength | Elongation | Hardness |
≥ 760 MPa | ≥ 350 MPa | ≥ 40% | ≤ 100 HRB |
Table 3: Typical Physical Properties of Hastelloy B2
These physical properties highlight the material's ability to perform reliably under a wide range of conditions.
Density | Melting Point | Thermal Expansion | Thermal Conductivity | Modulus of Elasticity | Electrical Resistivity |
9.22 g/cm³ | 1330-1380 ℃ | 10.3 µm/m·℃ | 9.1 W/m·K | 205 GPa | 1.37 µΩ·m |
These physical properties make the alloy suitable for heat exchangers, reactors, and distillation equipment operating in corrosive environments.
Industrial Applications of Seamless Hastelloy B2 Pipes
Due to its exceptional resistance to reducing acids, Hastelloy B2 pipes are widely used in industries requiring high corrosion resistance and process reliability.
Chemical Processing
Common applications include equipment used in the production of:
- Plasticizers
- Magnesium chloride
- Organic acids
- Agricultural chemicals
Petrochemical Processing
Hastelloy B2 pipes are used in:
- Catalytic alkylation units
- Isomerization processes
- Acid-resistant process piping
Pharmaceutical Industry
The alloy is suitable for high-purity reactors and chemical processing equipment where aggressive reducing reagents are used.
Vacuum and Distillation Systems
Seamless Hastelloy B2 pipes are also applied in:
- Vacuum distillation columns
- Acid-resistant heat exchangers
- Chemical processing pipelines operating under reduced pressure conditions
Quality Assurance and Traceability
EverySeamless Hastelloy B2 Pipe is manufactured under strict quality management procedures to ensure full compliance with international industrial standards.
Material Verification
- 100% PMI (Positive Material Identification) to confirm chemical composition.
Non-Destructive Testing
- Ultrasonic Testing (UT)
- Hydrostatic pressure testing
- Eddy Current Testing (ET)
Certification and Documentation
Complete documentation ensures full traceability, including:
- EN 10204 3.1 / 3.2 Material Test Certificates
- Third-party inspection reports from SGS, ABS, or Lloyd’s Register
- Intergranular Corrosion (IGC) testing reports
Important Technical Considerations for Hastelloy B2
Although Hastelloy B2 performs exceptionally well in reducing environments, several conditions must be carefully controlled to ensure long-term performance.
Avoid Oxidizing Contaminants
Hastelloy B2 has limited resistance to oxidizing media. The presence of oxidizing ions such as:
- Ferric ions (Fe³⁺)
- Cupric ions (Cu²⁺)
- Nitrates
can significantly accelerate corrosion.
Recommended Solution:
If oxidizing impurities are present in the process stream, alloys such as Hastelloy C276 or Hastelloy B3 may be more suitable.
Intermediate Temperature Sensitivity
Hastelloy B2 can experience embrittlement when exposed to temperatures between 600°C and 800°C, where brittle intermetallic phases may form.
Best Practice
- Strict control of welding parameters
- Rapid cooling after thermal exposure
- Use of qualified welding procedures
Limitations in Oxidizing Environments
Although B2 is highly resistant to chloride-induced SCC, it should not be used in strong oxidizing environments, such as:
- Nitric acid service
- Wet chlorine gas exposure
In these conditions, corrosion rates may increase significantly.
