Industries & Professions /
Welders and Welding Technicians
Welders use various kinds of equipment and processes to create the heat and pressure needed to melt the edges of metal pieces in a controlled fashion so that the pieces may be joined permanently. The processes can be grouped into three categories. The arc welding process derives heat from an electric arc between two electrodes or between an electrode and the workpiece. The gas welding process produces heat by burning a mixture of oxygen and some other combustible gas, such as acetylene or hydrogen. The resistance welding process obtains heat from pressure and resistance by the workpiece to an electric current. Two of these processes, the arc and gas methods, can also be used to cut, gouge, or finish metal.