Exothermic welding, also known as Exothermic Bonding, Thermite Welding, and Thermit Welding, is a welding process that utilizes molten metal to permanently join conductors. The process relies on an exothermic reaction of a thermite composition to heat the metal, eliminating the need for an external heat source or current. The heat is generated through an alumino-thermic reaction between aluminum powder and a metal oxide.

Exothermic welding is primarily used for welding copper conductors but is also suitable for a wide range of metals, including stainless steel, cast iron, common steel, brass, monel, and bronze. It is particularly beneficial for joining dissimilar metals.