Weld symbols are used for designers to communicate with welders by placing welding information onto drawings as part of a metal fabrication project.
BS EN 22553 is the British standard for weld symbols which provides the rules for the symbolic representation of welded, brazed and soldered joints on drawings. This has now been superseded by BS EN ISO 22553.
What Is A Welding Symbol?
A basic welding symbol skeleton can include up to six elements:
- Reference Line
- Dash Line
- Leader Line
- Weld Symbol
The image above is a Welding Symbol (not to be confused with a weld symbol). The Tail is not always used as it is a place for extra information on the weld which may include a reference to the welding process, a detail drawing, the electrode or any additional information which aids with the weld but does not have its own place on the welding symbol. For example, with a Stitch Weld where numbers are present on the Tail, these will indicate the size of both the weld itself and the gap between the welds.
The Reference Line is always drawn horizontally and provides information on where all the other welding symbols are tied. Coming off of this is the Leader Line which connects the Arrow’s head to the reference line.
What Are Basic Weld Symbols?
If the weld symbol is placed above the solid reference line, then the symbol will be applicable to the opposite side of the joint:
Information relating to the arrow side of the weld joint will be found below the solid reference line typically where the Dash Line is located:
A Dash Line is used in ISO systems and not in others such as AWS systems, for example. The Dash Line may be found either above or below the reference point, but this does not change anything regarding placements as a weld symbol placed below the solid reference line remains applicable to the arrow side of the joint and vice versa. If, however, the weld symbols are symmetrical the dash line is omitted, and the weld will be performed on both sides of the joint:
Symbols Used in Welding
Elementary Weld Symbols
Below we have elementary weld symbols and their associated symbol which would be used on the drawing.
Supplementary Weld Symbols
Supplementary weld symbols are used in addition to Elementary Weld Symbols, not on their own.