Seam Weld Symbol
How to read a seam Symbole de soudure — the circle with a horizontal line through its center. Width, length, pitch, and why the process designation in the tail is mandatory.
Seam Weld Symbol Dimensions
Per AWS A2.4 §12, seam Symboles de Soudage follow the same general dimension rules as spot welds, with added length and pitch for intermittent seam welds.
Where Each Dimension Goes
Width (Dimension de soudure) — to the LEFT of the symbol. This is the width of the seam weld nugget or bead.
Length — to the RIGHT. For continuous seam welds, length is the total weld length. For intermittent, it appears as part of the length-pitch format.
Pitch — to the RIGHT, in length-pitch format (e.g. 2-4 means 2-inch weld segments at 4-inch center-to-center spacing).
Number of seam welds — in parentheses.
Process — REQUIRED in the tail. Per A2.4 §12.1.3, the Procédé de Soudage must be specified: RSEW, GTAW, GMAW, etc.
Three Placement Options
Below reference line — Côté flèche. The seam weld is on the side the arrow points to.
Above reference line — Autre côté.
Centered on reference line — no side significance. Used for RSEW (resistance seam Soudage) where the weld forms between members regardless of which side faces the Électrode. Per A2.4 Figure 12.1, EBW has side significance and is placed above or below the Ligne de référence.
Resistance vs Arc Seam Welding
The same seam weld symbol represents fundamentally different processes. The tail designation determines which one.
| Feature | Resistance Seam (RSEW) | Arc Seam (GTAW/GMAW) |
|---|---|---|
| Equipment | Rotating wheel electrodes | Standard Soudage à l'Arc torch |
| Side significance | None — center on ref line | Yes — arrow/other side |
| Material range | Thin sheet (typically <3mm) | Wider range, thicker material |
| D1.1 scope | Outside D1.1 scope | Arc process rules apply |
| Applications | Automotive, tanks, leak-tight joints | Less common in structural work |