Welding is a fabrication process that joins materials, typically metals or thermoplastics, by causing coalescence. This joining is achieved by heating the work area to the material’s melting point and often by introducing an electrode or filler material. The precise technique employed determines the resulting metallurgical structure; methods vary in their ability to manage heat input, penetration depth, and shielding of the molten pool. Different variations of the process utilize various forms of electrical or thermal energy, such as electric arc energy, resistance heating, or directed gas streams, to maintain the necessary conditions for bonding. The controlled application of heat and the potential use of flux or inert shielding gases are critical to forming a stable, structurally sound joint that resists mechanical stress and environmental degradation.