Welders join or sever metals in beams, girders, vessels, piping and other metal components, make metal parts used in construction and manufacturing plants, and weld parts, tools, machines and equipment.
Welding usually involves applying heat to metal pieces to melt and fuse them together. In electric arc welding, heat is created as an electric current flows through an arc between the tip of the welding electrode and the metal. In gas welding, such as oxy-acetylene welding, the flame from the combustion of burning gases melts the metal. In both arc and gas welding, filler materials are melted and added to fill the joint and make it stronger. In resistance welding, the metal piece itself is melted as current flows through it, and no filler is added.
Welders use different welding processes and fillers depending upon the type of metal, its size and shape, and requirements for finished product strength. For a typical welding project, they:
Welders may also build up worn parts by welding layers of high-strength hard-metal alloys onto them.