Hastelloy B3 is a nickel‑molybdenum alloy with improved thermal stability and excellent resistance to reducing environments. It exhibits outstanding corrosion resistance to hydrochloric acid, sulfuric acid, and other pure or mixed reducing acids. Compared to Hastelloy B2, it has better resistance to precipitation and cracking during welding and heat treatment. It offers good ductility, formability, and mechanical properties, making it highly suitable for severe corrosive applications requiring long‑term reliability.