Hastelloy B2 Welded Pipes: Superior Corrosion Resistance for Critical Applications

In industries dealing with highly aggressive chemicals and extreme environments, material selection is crucial for ensuring system longevity and safety. Hastelloy B2 Welded Pipes, known for their exceptional resistance to reducing environments, are a reliable choice for applications where standard stainless steels and other alloys fail.

In this blog, we’ll explore what makes Hastelloy B2 Welded Pipes stand out, their advantages, and the industries where they are most commonly used.

What is Hastelloy B2?

Hastelloy B2, designated as UNS N10665, is a nickel-molybdenum alloy developed to offer outstanding resistance to hydrochloric acid, hydrogen chloride gas, and other strongly reducing media. It is part of the broader Hastelloy family developed by Haynes International and is tailored for demanding chemical processing conditions.

Key Alloying Elements:

Nickel (Ni): ~69%

Molybdenum (Mo): ~28%

Iron (Fe): Very low

Carbon (C): Extremely low for enhanced weldability

Features of Hastelloy B2 Welded Pipes

Excellent Corrosion Resistance

Hastelloy B2 performs exceptionally well in:

Hydrochloric acid (HCl) at all concentrations and temperatures

Sulfuric, acetic, and phosphoric acids

Hydrogen chloride gas and wet H₂S environments

 Resistance to Stress Corrosion Cracking

With low carbon, iron, and silicon content, B2 minimizes the risk of stress corrosion cracking and intergranular attack, especially after welding.

Good Weldability

Hastelloy B2 is designed with low impurity content, ensuring clean, high-integrity welds with minimal risk of grain boundary precipitation.

 High Thermal Stability

Maintains strength and corrosion resistance at elevated temperatures, making it suitable for heat exchanger and reactor use.

Applications of Hastelloy B2 Welded Pipes

Due to its unique corrosion-resistant profile, Hastelloy B2 welded pipes are used in some of the most aggressive industrial environments:

 Chemical Processing Industry

Heat exchangers, reactors, and vessels

Acid regeneration units

Transfer piping for hydrochloric acid and other reducing agents

 Oil & Gas Refining

Sour gas processing

Injection and recovery systems

Acid gas removal units

 Pharmaceutical & Food Industry

Piping in acid-cleaning systems

Process lines exposed to aggressive cleaning agents

Water Treatment

Desalination plant piping exposed to harsh cleaning chemicals

Brine filtration systems

 Nuclear and Aerospace

Systems exposed to extreme conditions involving heat, radiation, and corrosive media

Advantages of Welded Over Seamless in Some Applications

While seamless pipes are traditionally preferred in high-pressure environments, welded pipes offer several advantages, especially for Hastelloy B2:

 Cost-effectiveness for larger diameters and lower-pressure applications

 Quick lead times due to easier fabrication

 Better availability in customized lengths and thicknesses

 Excellent performance when properly welded using recommended procedures

Specifications & Standards

Hastelloy B2 Welded Pipes are typically manufactured to the following standards:

ASTM B619 – Welded Pipe

ASTM B622 – Seamless Pipe (for reference)

ASME SB619

Available in various diameters, schedules, and custom lengths, they can be further tested for:

Hydrostatic testing

PMI (Positive Material Identification)

Radiographic and ultrasonic inspection (on welds)

Important Considerations When Using Hastelloy B2

 Avoid oxidizing media: B2 is not suitable for oxidizing acids (e.g., nitric acid).

 Proper fabrication techniques are essential to maintain corrosion resistance, especially post-weld cleaning and passivation.

 Store and handle carefully to prevent contamination and preserve corrosion performance.

Besides corrosion resistance, the welded pipes are also easy to fabricate, which makes them more attractive in industries. Hastelloy B3 Welded Pipes are easily formed, welded, and machined-a characteristic of the material that becomes helpful in industries that demand custom or complex piping configurations. Reliable Steel Distributors also provides customization options, thereby allowing clients to get the hastelloy B3 pipes in various dimensions and thicknesses, tailor-made as per specific project requirements.

Specifications : ASTM B 622 ASME SB 622 / ASTM B 619 ASME SB 619

Dimensions : ASTM, ASME, and API

Size : 15″NB TO 150″NB IN

Specialized in : Large Diameter Size

Schedule : SCH5, SCH10, SCH40, STD, SCH80, SCH160

Type : Seamless / ERW / Welded / Fabricated

Form : Round, Hydraulic Etc

Length : Single Random, Double Random & Cut Length.

End : Plain End, Beveled End, Treaded