⊗ Stud weld
Stud weld · Soldadura en plano · ISO 1101 + ASME Y14.5
Example in plan
How to interpret it
On the drawing, “M8 stud welded per ISO 14555” states a stud weld requirement.
What controls
Attachment of a stud, bolt or pin to a sheet or structure by simultaneously melting the tip of the stud and the base surface, so it is joined over its whole contact cross-section without any need to drill. The symbol is accompanied by the stud designation, its location and the number of studs. It is a process requirement as well as a geometric one: the result depends almost entirely on machine parameters and surface preparation.
How to verify
The standard check is the bend test: the stud is bent through a specified angle with a tube or bending tool and must not break or come away from the base. It is performed on the first studs of each batch and periodically, in addition to visually inspecting the collar of material around the full circumference. Height above the surface and location are measured with calipers and a template; squareness with a square.
Common mistakes when interpreting it
- Accepting the stud because it does not move when pulled by hand: the valid check is the bend test, not feel.
- Welding over a painted or galvanized surface without cleaning it and trusting the arc to burn it off.
- Torquing the nut on a freshly welded stud that is still hot, which is when it is weakest.
How to get it in the workshop / if it comes out of tolerance
The surface must be free of paint, rust and galvanizing in the contact area; over a coating the stud bonds poorly even if it looks fine. Check the squareness of the stud before it cools, because afterward it cannot be corrected without removing it. The annular fillet (flash collar) that forms at the base is a visual indicator that fusion was uniform all around.
Incomplete collar on one side: the gun was not perpendicular or the stud was not sitting flat; correct the position before continuing with the batch. Studs that come off in the bend test indicate insufficient arc time or lift, or a dirty surface. If the base material is thin, welding can mark or bulge the opposite face: that is an effect to assess beforehand, not a defect that can be polished out afterward.
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