Welding

Welding is the joining together of materials (typically metals or thermoplastics), usually by a fusion process. Most commonly, workpieces are welded by melting both of them and adding more molten metal or plastic to form a pool that cools to form a strong joint. The energy to form the joint between metal workpieces most often comes from a flame (e.g. oxyacetylene) or an arc, but welding by laser beam, electron beam and friction processes is well established. Energy for welding of thermoplastics typically comes from direct contact with a heated tool or a hot gas.

Types of welding

• Manual metal arc welding, or 'stick' welding is the most common form;
• Gas welding[?];
• Friction welding[?];
• Metal inert gas (MIG);
• Tungsten inert gas (TIG);
• Spot welding;
• Submerged arc welding;
• Explosive welding[?];
• Stud welding[?];
• Laser welding[?].