English: Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, but sometimes pressure is used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involve melting a lower-melting point material between the workpieces to form a bond between them. Many different energy sources can be used for welding, including oxy-acetylene gas, an electric arc, a laser, an electron beam, friction, and ultrasound. While often an industrial process, welding can be done in many different environments, including open air, underwater and in space. Regardless of location, however, welding remains dangerous, and precautions must be taken to avoid burns, electric shock, poisonous fumes, and overexposure to ultraviolet light.
Español: La soldadura es la unión de dos materiales (generalmente metales) a través de un proceso de fusión en el cual las piezas son soldadas derritiendo ambas y agregando metal o plástico derretido para conseguir una "pileta" (punto de soldadura) que, al enfriarse, forma una unión fuerte.
A seaman in the U.S. Navy demonstrates oxy-fuel cutting.
Steel armature is welded to make the proper adjustments for a phytosaur skull to be put on display at a museum.
Air Force journeyman preparing to weld
A man gas metal arc welding.
Partial weld around a pipe joint with clear heat affected zone. This is ASME SA106 Grade B steel pipe NPS 2.5 SCH 80 with J-grooved prepared ends. An automated TIG orbital welder made half an orbit before aborting. The heat affected zone is clearly visible because of the polished ends, even though it is generally inoccuous in this material. (SA106 Grade B)
The four most types of joints, commonly used in welding, soldering, and brazing applications. Number 1 is a square butt joint, 2 is a single V preparation joint, 3 is a lap joint, and 4 is a T-joint.
A cross-section of a welded butt joint, with shading that shows the locations of the fusion zone (darkest gray) and the heat-affected zone (middle shade of gray) in the base material (lightest gray).
SVG VERSION. The four most types of joints, commonly used in welding, soldering, and brazing applications. Number 1 is a square butt joint, 2 is a single V preparation joint, 3 is a lap joint, and 4 is a T-joint.