Edge Weld Symbol
How to read an edge weld symbol — the two parallel lines indicating a weld joining flanged or parallel edges. Common in sheet metal, less common in structural steel. When to combine with melt-through.
Edge Weld Symbol Dimensions
Per AWS A2.4 §13, the edge weld symbol is two short parallel vertical lines on the reference line. It represents a weld that fuses the full thickness of both member edges.
Where Each Dimension Goes
Size — to the LEFT when specified. This is the weld width or buildup thickness.
Length — to the RIGHT. The extent of the edge weld along the joint.
Joint Types
Parallel edge joint — two members with edges aligned side by side. The weld fuses the edges together.
Flanged butt joint — thin members with edges flanged (bent) to create a preparation for welding from one side.
Flanged corner joint — one or both members flanged at a corner. The flange creates material for the weld.
Combining with Melt-Through
When CJP is required on a flanged joint welded from one side, add the melt-through symbol (filled semicircle) on the opposite side of the reference line. This combination tells the welder that full penetration with visible root reinforcement is required.