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A butt weld symbol is an elementary symbol and can be illustrated in various forms. they can also be combined to indicate weld from both sides.
Weld symbols are used in technical drawing to transfer information from the design to the fabrication floor, it standardizes the communication between all the people involved in the job. Weld symbols form part of a welding symbol which are graphically represented with a reference horizontal line and the arrow line. Additional details on the tail of a welding symbol may be used.
The graphical representation will depend on the type of standard in use. There are two main recognized standards around the globe, the European Standard in combination with ISO, and the American standard issued by the American Welding Society (AWS).
What is a butt weld?
It is a weld type in which the two adjacent surfaces to be welded are aligned next to each other. The alignment planes should be as close as possible to an angle of 180o. A change in the aligned angle outside a certain range may result in another type of weld being formed.
Where are butt welds commonly used?
It’s widely used within the metal fabrication industry. They are used in pipeline installation to weld the two pipe ends together. They are used in the production of seam welded pipe and they are also to weld flange to pipe.
In pressure vessel construction, butt welds are used to make the circumferential weld between the vessel head to the shell and to weld other longitudinal welds within the shell body.
The choice of the weld type, butt weld vs other types, is determined during the design phase. Several factors are considered when selecting the weld type, e.g., type of load (dynamic or static), the direction of the applied load, serviceability, accessibility, corrosion, cost, material size, etc.
What are the different types of butt weld joints?
Types of butt welds on single-sided and double-sided joints:
- Square butt weld
- Single V
- Single V with broad root face
- Double V
- Single bevel
- Double bevel
- Single bevel with broad root face
- Single U
- Double U
- Single J
- Double J
- Flanged butt
- Steep flanked single V
- Steep flanked single bevel
Illustration and Description of Butt Weld Symbols
| Weld Type | Description | Symbol | Illustration |
|---|---|---|---|
| Square butt | Buttweld without a bevel or groove preparation. The ends to be welded are squared. |  |  |
| Single V | Butt with a groove in V shape welded from one side. |  |  |
| Single V with broad root face | V-shaped groove welded from one side with an extended root face. |  |  |
| Double V | With a groove in form of X or double V, welded from both sides. |  |  |
| Single bevel | With a groove in half V shape welded from one side. Only one member is beveled |  |  |
| Double bevel | With a groove in K shape welded from both sides. Only one member is beveled. |  |  |
| Single bevel with broad root face | With a groove in half V shape welded from one side with extended root face. Only one member is beveled. |  |  |
| Single U | With a groove in U shape welded from one side. |  |  |
| Double U | With a groove in double U shape welded from both sides. |  |  |
| Single J | With a groove in J shape welded from one side. |  |  |
| Double J | With a groove in double J shape welded from both sides. |  |  |
| Flanged butt or corner weld | Buttweld on the edge of two surfaces that forms a natural groove. |  |  |
| Steep flanked single V | Buttweld in form of a V and cut on the bottom. |  |  |
| Steep flanked single bevel butt | In form of a half V and cut on the bottom. |  |  |
Conclusion
These symbols form part of a welding symbol. A weld symbol when used in a technical drawing, certain rules need to be followed according to the applicable standard.
A proper welding symbol should contain information regarding the weld symbol, the indication of the member to be grooved, weld size, complete or partial penetration weld, and some additional information if needed.
