Hastelloy B (UNS N10001, W.Nr. 2.4800) is a classic nickel-molybdenum (Ni-Mo) solid solution strengthened corrosion-resistant superalloy, developed by the Hastelloy International Company. This alloy is characterized by its high molybdenum content and extremely low chromium content, and is specifically designed for strongly reducing environments. It exhibits excellent tolerance in hydrochloric acid, hydrogen chloride gas, sulfuric acid, phosphoric acid, and various non-oxidizing chemical media. Since its development, it has been widely used in the chemical processing industry, petrochemicals, pharmaceuticals, environmental engineering, and energy sectors.
Hastelloy B (UNS N10001, W.Nr. 2.4800) is a classic nickel-molybdenum (Ni-Mo) solid solution strengthened corrosion-resistant superalloy, developed by the Hayess International Company. As the base grade of the Hayess B alloy family, it is characterized by a high molybdenum content and an extremely low chromium content. This alloy is specifically designed for use in strongly reducing environments and has excellent tolerance to hydrochloric acid, hydrogen chloride gas, sulfuric acid, phosphoric acid, and various non-oxidizing chemical media. Since its development, it has been widely used in the chemical processing industry, petrochemicals, pharmaceuticals, environmental engineering, and energy sectors.
One of the main advantages of Hastelloy B is that it can maintain stable corrosion resistance and mechanical properties over a wide range of corrosive media and temperatures. Its high molybdenum content provides special tolerance to reducing acids (especially hydrochloric acid), while the extremely low chromium content design enhances its performance in non-oxidizing media. By carefully controlling the content of chromium and iron, the formation of harmful intermetallic phases is minimized, enabling the alloy to have excellent stability and corrosion resistance under harsh chemical processing conditions.
This alloy possesses a stable face-centered cubic (FCC) austenite matrix structure. As a solution strengthened alloy, Hastelloy B does not rely on the γ′ precipitation strengthening phase. Its strength mainly stems from the solid solution strengthening effect provided by the molybdenum atoms dissolved in the nickel-based austenite matrix, thereby endowing the alloy with excellent microstructure stability and minimizing performance degradation during long-term service.
Hastelloy B exhibits outstanding corrosion resistance in reducing environments, with excellent tolerance to hydrochloric acid, hydrobromic acid, phosphoric acid, and various organic acids. This alloy also demonstrates excellent resistance to chloride stress corrosion cracking and maintains good corrosion resistance in high-purity chemical media and harsh acidic environments, making it particularly suitable for applications in the chemical processing and petrochemical fields.
This alloy also possesses excellent manufacturing and processing characteristics, including good weldability, formability and machinability. It can be easily processed through operations such as forging, rolling, welding and machining. Therefore, Hastelloy B is widely used in salt acid production equipment, acid washing systems, reactors, heat exchangers, pumps, valves and various corrosion-resistant engineering equipment.
Hastelloy B adopts the traditional Ni-Mo solid solution strengthening alloy system. Its mechanical properties are mainly achieved through solid solution strengthening rather than precipitation hardening.
Nickel (Ni): Balance
Molybdenum (Mo): 26.0–30.0
Iron (Fe): 4.0–6.0
Chromium (Cr): ≤1.0
Cobalt (Co): ≤2.5
Vanadium (V): 0.2–0.4
Manganese (Mn): ≤1.0
Silicon (Si): ≤1.0
Carbon (C): ≤0.05
Phosphorus (P): ≤0.04
Sulfur (S): ≤0.03
These alloying elements jointly form a stable face-centered cubic (FCC) austenite matrix structure. The high molybdenum content provides excellent tolerance to reducing environments (especially hydrochloric acid), while the extremely low chromium content design enhances performance in non-oxidizing corrosive media. By carefully controlling the chromium and iron contents, the formation of harmful intermetallic phases is minimized, thereby improving the stability and corrosion resistance of the alloy under harsh chemical processing conditions.
Hastelloy B can maintain excellent mechanical properties and structural stability under high-temperature and highly corrosive operating conditions. The density of this alloy is approximately 9.22–9.24 g/cm³, and its melting range is approximately 1330–1418°C.
Its microstructure is mainly composed of a stable face-centered cubic (FCC) nickel-based solid solution matrix, which exhibits excellent metallurgical stability. This alloy can still maintain good ductility, toughness and strength even after being exposed to high-temperature environments for a long time.
The solid solution strengthening mechanism provides excellent high-temperature strength, structural stability and heat fatigue resistance. Therefore, this alloy can withstand harsh thermal cycling conditions while maintaining structural integrity and mechanical reliability.
Furthermore, Hastelloy B exhibits excellent tolerance to hydrochloric acid, hydrobromic acid, phosphoric acid, and various organic acids, and demonstrates outstanding resistance to chloride stress corrosion cracking. Its high molybdenum content endows it with outstanding corrosion resistance in reducing environments, while the stable nickel-based structure ensures reliable performance during long-term service, making it the preferred material for demanding applications such as chemical processing, petrochemicals, and pharmaceuticals.
Hastelloy B can be produced through hot rolling, cold rolling, forging, drawing and manufacturing processes. This alloy offers a variety of product forms for selection, including sheets, strips, bars, tubes, pipe fittings, forgings and welded components, and it has excellent thermal and cold working properties.
Heat processing performance
This alloy exhibits excellent heat processing properties and can be formed through processes such as forging and hot rolling. During heat processing, it is recommended to uniformly heat the material to an appropriate temperature range and control the amount of deformation to avoid internal cracks or poor microstructure.
Cold working performance
Hastelloy B exhibits excellent cold working properties and can be processed through cold rolling, cold drawing, and cold forming techniques. However, due to its high molybdenum content, this alloy has a significant tendency towards work hardening. During the cold working process, the material rapidly hardens, so intermediate annealing treatment may be required to restore plasticity and facilitate subsequent processing.
Part Two: Hastelloy B
Used in hydrochloric acid production equipment, acid washing systems, reactors, evaporators, and systems for handling corrosive chemicals.
It is applied to acid treatment equipment, chemical reaction systems, and corrosion-resistant pipeline networks.
Equipment and processing systems used for handling highly pure corrosive media.
Suitable for smoke gas treatment systems, waste acid recovery devices, and corrosive wastewater treatment facilities.
Applied to high-temperature heat exchange equipment and corrosion-resistant structural components operating in harsh high-temperature environments.
It is widely used in pumps, valves, piping systems, pressure vessels, and various corrosion-resistant engineering equipment.
