Exothermic welding, sometimes referred to as exothermic bonding or thermite welding, is a technique for permanently joining two or more conductive metal components together electrically. Applications including electrical grounding, lightning protection, and linking rail tracks all frequently use this method.

In exothermic welding, a metal oxide and a powdered metal combination react chemically in a mold made of graphite. The exothermic welding powder, which is made of finely powdered metals and metal oxides, is the main ingredient in this procedure. Aluminium and copper are the two main metals used in exothermic welding powders, while additional materials can be utilized depending on the particular application.

The typical elements of exothermic welding powder are summarized as follows:

Metal Fuel: In exothermic welding powder, aluminium is frequently used as the fuel. In the chemical reaction, it acts as the reducing agent. Aluminium interacts with metal oxides to form molten metal when burned.

Metal Oxide: Metal oxides are employed as oxidizing agents, such as iron oxide. These oxides supply the oxygen needed for the metal fuel's combustion process.

Other Additives: To aid in the ignition and regulation of the reaction, exothermic welding powders may also include extra ingredients such fluxes and ignition materials.

The following steps are part of the exothermic welding process:
The metal parts that will be connected are cleaned and placed correctly inside a graphite mold as part of the preparation process. The metal components will be held in the mold in the desired arrangement.

Exothermic reaction in welding powder is started by an igniting source, such as a magnesium strip or an electric igniter.

process: The metal fuel, such as aluminium, reacts with the metal oxide, such as iron oxide, in the powder to start the exothermic process. This reaction generates a large quantity of heat and causes the metal to become molten.

Bonding: When molten metal flows into the space between metal parts, it joins them like a weld. An extremely robust, long-lasting electrical connection is created as the liquid metal cools and solidifies.