Types Of Butt Joint Welds

Types Of Butt Joint Welds

1 Tack Welds

Prevent butt joint distortion by tack weldingthe materials in position before final weld.

Workpiece distortion occurs when heat is applied locally to a joint. One side of a metal plate will “curl” up toward the weld.

Distortion will also cause the edges of a butt joint to pull together ahead of the electrode as the weld cools.

2 Square Groove Weld

3 Single V-Groove Weld

4 Double V-Groove Weld

Materials up to 3/16 in (5 mm) thick can often be welded without special preparation using the square groove weld. However, when welding thicker materials it may be necessary to prepare the edges (V-groove) of butt joints to ensure good welds.

DESIGN CONSIDERATIONS FOR WELDING

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.

PRINCIPLES OF SHIELDED METAL ARC WELDING (SMAW)

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.