Thermite welding, also known as exothermic welding, is a welding process that uses heat from an exothermic reaction to achieve coalescence between two metals. Thermite is the term used for the combination of iron oxide (or the oxides of other metals) and aluminum in powder form. During the welding process, the thermite is ignited using an external source of heat and reaction between the two materials results in aluminum-oxide and extremely high heat that provides the weld.

The thermite welding process is composed of several phases. The pieces of metal to be welded need to be prepared through cleaning, the welding gap needs to be set and the ends of the metal pieces need to be preheated. After the welding is complete, the weld needs to be cleaned through rough grinding, then through the final grinding to achieve the required smoothness of the surface.

Thermite welding is suitable for welding a wide range of different metals and alloys, including steel, stainless steel, bronze, cast iron as well as for copper conductors, being the only acceptable method for bonding copper to galvanized cable. The technology is also commonly used in welding the ends of railroad tracks as well as in the ship building industry.  For help with construction excavation services look to professionals like Hydrodig.