Apart from resistance spot welding (RSW), three processes are most commonly used for welding metal stampings and fabrications: gas metal arc welding (GMAW) or MIG; gas tungsten arc welding (GTAW) or TIG; and gas welding.
Although a high initial investment is necessary, laser welding is being more widely employed by companies requiring large quantities of multi-point welds. This method employs robots, welding at speeds of up to 150 inches (3.8 m) per minute. Other processes--plasma arc, ultrasonic, and electron beam welding--are also available, but these methods are usually restricted to welding of particular materials with special design requirements, such as microelectronic and aerospace components. Suitability for general sheet metal applications is limited, and processing may be cost-prohibitive.
Shielded Metal Arc Welding (SMAW) or Stick welding is a
process which melts and joins metals by
heating them with an arc between a coated metal electrode and the workpiece. The
electrode outer coating, called flux, assists in creating the arc and provides
the shielding gas and slag covering to protect the weld from contamination. The
electrode core provides most of the weld filler metal.When the electrode is moved along the workpiece at the
correct speed the metal deposits in a uniform layer called a bead.
