Welding symbols chart
The building blocks of an AWS welding symbol and the common weld types it can call out. Use it to read a weld symbol on a drawing: where the weld goes, what shape it is, and how big.
Weld types
| Weld type | Symbol | Symbol shape | Where it is used |
|---|---|---|---|
| Fillet | Right triangle | Lap, tee, and corner joints (the most common weld) | |
| Square groove | Two parallel lines | Butt joints in thin material, no edge prep | |
| V-groove | V shape | Butt joints with both edges beveled | |
| Bevel groove | Single slanted line | Butt joints with one edge beveled | |
| U-groove | U shape | Thick butt joints with U-shaped prep | |
| J-groove | J shape | Butt or tee joints with one J-prepped edge | |
| Plug or slot | Rectangle | Weld through a hole or slot in the top part |
Parts of a welding symbol
| Element | Meaning |
|---|---|
| Reference line | Horizontal line that carries all the weld information |
| Arrow | Points to the joint to be welded |
| Tail | Holds the process, spec, or other notes |
| Symbol below the line | Weld on the arrow side of the joint |
| Symbol above the line | Weld on the other (far) side |
| Symbol on both sides | Weld both sides of the joint |
| Circle at the bend | Weld all around the joint |
| Filled flag at the bend | Field weld, made on site rather than in the shop |
Position is the key rule: a weld symbol below the reference line means the weld is on the arrow side, and above the line means the other side. Numbers to the left of the symbol give the weld size; numbers to the right give length and pitch for intermittent welds.
Sizing a weld or structural member?
Browse the engineering calculators for structural tools, or see the other reference charts for material strengths.
Arrow side vs other side
The most important part of reading a weld symbol is which side of the reference line the weld symbol sits on. Below the line means the weld is on the side the arrow points to, the arrow side. Above the line means the far side. Symbols on both sides call for welds on both faces of the joint.
Size, length, and spacing
A fillet weld symbol carries its leg size as a number just to the left of the triangle. To the right, numbers give the weld length and, for intermittent welds, the pitch or center-to-center spacing. A weld-all-around circle at the bend in the reference line means the joint is welded around its full perimeter.
FAQ
What does a weld symbol below the line mean?
The weld is on the arrow side of the joint, the side the arrow points to. A symbol above the line means the weld is on the other side.
What is the most common weld symbol?
The fillet weld, drawn as a right triangle. Fillet welds join overlapping or perpendicular parts in lap, tee, and corner joints.
What does a flag on a weld symbol mean?
A filled flag at the bend in the reference line marks a field weld, one made during installation on site rather than in the fabrication shop.