Weld Symbol Decoder

Interpret welding symbols per AWS A2.4 standard. Select symbol components to decode.

Weld Type

Symbol Location

Arrow side = weld on the side the arrow points to

Size/Leg (mm or in)

Length (mm or in)

Pitch/Spacing

Groove Angle

Root Opening

Root Face

Contour

Finish Method

Supplementary Symbols

Field Weld (flag symbol) Weld All Around (circle) Melt-Through Required Backing Bar/Strip Used Spacer Used

AWS A2.4 Quick Reference

Symbol	Meaning	Location
Triangle	Fillet Weld	Arrow/Other side
V shape	V-Groove	Open side down = arrow
Half V	Bevel Groove	Perpendicular leg on arrow
Flag	Field Weld	At reference line junction
Circle	Weld All Around	At reference line junction
Filled circle	Spot/Projection	Arrow/Other side

Understanding Weld Symbols

AWS A2.4 Standard Elements

Reference Line: Horizontal line that carries the weld symbol information
Arrow: Points to the joint where the weld is to be made
Weld Symbol: Indicates the type of weld (fillet, groove, etc.)
Dimensions: Size, length, pitch placed around the symbol
Tail: Contains process, specification, or other reference info

Arrow Side vs Other Side

Arrow Side: Symbol below reference line = weld on side arrow points to
Other Side: Symbol above reference line = weld on opposite side
Both Sides: Symbols both above and below = weld both sides

Dimension Placement

Left of symbol: Weld size (leg length, throat, depth)
Right of symbol: Length, pitch (length-pitch format)
Inside symbol: Groove angle, root opening