**Abstract**

Resistance spot welding is one of the primary welding techniques extensively utilized in the automotive and aviation industries. Some 2000–3000 spots are made in a single body of automobiles, which are numerically controlled nowadays. Resistance spot welding works on the principle of Joule's law of heating, where the heat generated is directly proportional to the square of the welding current. This welding technique is generally used to join thin sheets of steel, titanium, aluminum, magnesium, etc. The welding of non-ferrous metals like aluminum and magnesium is quite tedious owing to their high thermal conductivities and the oxide formation on their surfaces. Thus extensive surface preparation is required before welding. Numerous limitations are also there in this welding technique which includes low strength of the joints and thickness limitation.

**Keywords:** resistance spot welding, welding current, welding time, automobile, Joule's law
