Welding symbols are critical information for welders to do their job perfectly. Welding symbols contain important information such as welding positions, welding processes, dimensions, geometry of the weld, groove/fillet details, etc. These symbols are presented graphically by the designer for the welders. You can say that it is a universal language in welding to maintain uniformity, consistency and accuracy.
Use of Welding Symbols on Drawings
The welding symbols indicate the welding processes deployed in metal joining operations. They show all information necessary to understand the basic shape and locations of welding components.
Welding Symbols with Examples
Here are the five most common welding symbols:
A groove weld is used to show parts coming together in the same plane. It is usually performed to make edge-to-edge joints but they are also sometimes used for corner joints, T joints, and joints between curved & flat pieces.
Groove-V gets its name from the V-shaped angle that it gets after the edges of both workpieces are cut off. There can be a single or double Groove-V, that is usually used for thicker materials because it is easy to apply the weld and create a stronger weld.
In groove-bevel, the edge of one workpiece is cut-off and the other one is left square. It needs less joint preparation as well as less weld metal. It is also used for thicker materials or when it is possible to modify one of the connecting components.
When the edge of one of the pieces gets concave treatment while the other one is left square, it results in a J-shaped angle known as groove-J. The groove cuts in less material which means less weld filler is used. However, groove-J is not as easy or affordable as groove-bevel.
The fillet weld symbol is represented as a right triangle placed on the reference line with the perpendicular leg on the left. It is used when the two members of the joint come together to form an intersection of 90 degrees. Fillet welds are generally used for boiler and pressure vessel manufacturing industries.
5. Back or Backing
A back weld is formed on the back side of the joint once the groove weld is performed. A backing weld, on the contrary, is applied to the root of the groove before the groove is welded. However, they both use the same symbols.
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