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Overview of the properties and application areas of Hastelloy B-2: The nickel-molybdenum alloy Hastelloy B-2 has extremely low levels of carbon and silicon, which reduces the precipitation of carbon and other impurity phases in the weld heat-affected zone; as a result, its welds also possess sufficient corrosion resistance. Hastelloy B-2 exhibits excellent corrosion resistance in reducing media, such as hydrochloric acid solutions at various temperatures and concentrations. It also exhibits excellent corrosion resistance in sulfuric acid solutions of moderate concentration (or those containing a certain amount of chloride ions). It can also be used in acetic and phosphoric acid environments. Alloy materials can achieve the best corrosion resistance only when they are in an appropriate microstructural state and have a pure crystal structure. It has wide applications in the fields of chemistry, petrochemicals, energy production, and pollution control, especially in industries such as sulfuric acid, hydrochloric acid, phosphoric acid, and acetic acid. Similar grades to Hastelloy B-2: NS322 (China), NiMo28 (France), W.Nr.2.4617 (Germany). Chemical composition of Hastelloy B-2: Alloy | Grade | % Nickel (Ni) | Chromium (Cr) | Iron (Fe) | Molybdenum (Mo) | Niobium (Nb) | Cobalt (Co) | Carbon (C) | Manganese (Mn) | Silicon (Si) | Sulfur (S) | Copper (Cu) | Aluminum (Al) | Titanium (Ti) Minimum values for Hastelloy B-2: 0.4, 1.6, 2.6, 0.0; Maximum values: 1.0, 2.0, 30.0, 1.0, 0.01, 1.0, 0.01, 0.5. Physical properties of Hastelloy B-2: Density in g/cm3, Melting point in °C, Thermal conductivity in λ/(W/m•°C), Specific heat capacity in J/kg•°C, Elastic modulus in GPa, Shear modulus in GPa, Electrical resistivity in μΩ•m, Poisson’s ratio, Linear expansion coefficient in a/10-6°C-1: 9.2, 13.3, 30, 138, 0.11 (at 100°C); 377, 217 at 20°C. Values range from 1.37 to 10.3 over the temperature range of 20–100°C. Mechanical properties of Hastelloy B-2: Minimum values measured at 20°C. Heat treatment methods and corresponding mechanical properties: Tensile strength σb/MPa, Yield strength σp0.2/MPa, Elongation σ5/%, Brinell hardness HBS. After solution treatment: 745, 325, 40; ≥250. Standards for manufacturing Hastelloy B-2: Standard bars, forgings, plates/strip, wires, tubes – American Society for Testing and Materials: ASTM B335, ASTM B335, ASTM B333, ASTM B622, ASTM B619, ASTM B626. Aerospace material specifications – American Society of Mechanical Engineers: ASME SB335, ASME SB335, ASME SB333, ASTM SB622, ASTM SB619, ASTM SB626. Microstructural structure of Hastelloy B-2: Hastelloy B-2 has a face-centered cubic crystal structure. By keeping the iron and chromium contents at minimum levels, processing brittleness was reduced, and the precipitation of the Ni4Mo phase in the range of 700–870°C was prevented. Process properties and requirements for Hastelloy B-2: 1. It should be heated to the required temperature as quickly as possible. The hot working temperature range is 1160°C to 900°C. 2. The average grain size of this alloy is closely related to the degree of deformation of the forging and the final forging temperature. 3. The adhesion of surface oxides, oxidation colors on the alloy, and slag around the welds is stronger than that on stainless steel; it is recommended to use fine-grained sand belts or fine-grained grinding wheels for polishing. 4. The alloy should be machined after annealing. Due to the high work hardening rate of the material, it is advisable to use lower cutting speeds and greater feed rates than those used for machining low-alloy standard austenitic stainless steels, in order to penetrate beneath the surface that has been hardened by cold working.