Welding symbols, like sign posts are informational directors. They are placed on drawings by Welding engineers and their purpose is to relay information to the weld operator. In many instances the information relayed is very simple.
Occasionally it is necessary for the engineer to relay complicated information. Therefore it is important that weld operators understand the symbols and are capable of interpreting the needs of the engineer.
For the most part weld symbols are standard throughout the world, although there are symbols that are devised and used only by the company that devised them.
Figure 001 shows the various elements of a Weld symbol and looks very busy. Lets break down the elements .
When we put the above elements together we see the result in fig. 007. The finished symbol instructs the weld operator to deposit a 1/4 fillet weld both sides of the joint and that the preferred welding rod will be a E7018.
Figure 008 looks very similar but in this case the symbol informs the weld operator that this is a stitch weld . The first Dimension indicates that each weld deposit is to be 3 in length. The second dimension refers to the center to center spacing requirement of each stitch. So in this case the weld operator is required to deposit a series of 3 welds with a 3 space between each deposit ( see fig 009 ).
Supplementary symbols are often added to the weld symbol. A supplementary symbol usually refers to pre - weld preparation or post weld finishing. fig 009 is an example of pre - weld preparation.
The symbol shown in figure 010 indicates that the vertical component requires beveling prior to assembly. The remainder of the symbol indicates that a 1/4 fillet is required to complete the weld. This symbol would usually be accompanied with additional notes and instruction. The additional notes would probably reference a specific weld procedure, which would indicate the number and sequence of multiple passes required to complete the finished weld.
The following illustrations show simple weld symbols and the resulting application.