Why is vacuum melting used for reactive metals such as titanium?

Vacuum melting is essential for reactive metals like titanium because of the metal's extreme chemical reactivity at elevated temperatures. In its liquid state, titanium is highly reactive and will readily reduce all known refractories, making standard melting containers unsuitable.1

Furthermore, titanium is highly susceptible to contamination by atmospheric gases such as oxygen and nitrogen when heated. By performing the melting process in a vacuum or an inert atmosphere (such as argon or helium), manufacturers can prevent these detrimental reactions, ensuring the purity and structural integrity of the final product.12

In industrial practice, this is often achieved through the consumable-electrode arc-melting process, where the metal is melted within a water-cooled copper crucible. This method not only protects the melt from atmospheric exposure but also allows for the removal of impurities and the uniform distribution of alloying elements.23