Weld symbol
Stud weld symbol
A circle crossed through calls for stud welding: a threaded or headed stud fused end-on to a surface in a single arc or resistance cycle, always on the arrow side.
Reads asArrow side: stud weld, 3/4 size, 12 pitch, 12 welds.
How to read it
The stud weld symbol is a circle with an X drawn through it. It describes a process rather than a joint geometry: a stud is held against the workpiece, an arc or a current pulse melts both mating faces, and the stud is plunged into the molten pool to fuse end-on to the surface. There is no groove and no fillet to dimension.
Because a stud is placed onto a surface rather than into a joint between two members, the symbol is always drawn on the arrow side of the reference line. There is no meaningful other side: the stud goes where the arrow points, on the face the arrow touches. Seeing this symbol above the line is a drafting error rather than an alternative reading.
The number to the left is the stud's diameter, and a count in parentheses says how many. A pitch to the right gives the centre-to-centre spacing where the studs run in an evenly spaced line, which is exactly how shear connectors are called out along a composite beam. Complex layouts are dimensioned on the drawing instead.
Stud welding's quality shows up at the collar of expelled metal around the base. A complete, even collar all the way round suggests the arc and plunge were right; a partial or missing collar on one side suggests the stud was not perpendicular or the arc was short. That is why bend testing a sample of studs is such a common acceptance step on shear connector work.
Where each dimension goes
- Stud diameter (left of the symbol)
- Shank diameter of the stud being welded to the surface.
- Count (in parentheses)
- How many studs the callout covers.
- Pitch (right of the symbol)
- Centre-to-centre spacing along a line of studs, as on shear connectors down a beam.
- Arrow side only
- The symbol always sits below the reference line, because a stud is placed on the surface the arrow touches.
Worked examples
Each one is a drawing, the sentence it comes out as, and then the mark-by-mark account of why. Read the sheet first and say the sentence yourself before you look down.
Example 1: Shear connectors along a beam
TitleShear connectors along a beamRefStud weldEx1 / 2Reads as
Weld twenty 3/4 diameter studs at twelve-inch centres along the top flange.
Which mark says so
- stud symbolBelow the reference lineA stud weld on the arrow side of the joint
- 3/4Left of the symbolSize of each weld - diameter for a spot, width for a seam
- -12Right of the length on the symbolPitch - centre to centre spacing of an intermittent weld
- (20)In parentheses beside the symbolHow many welds are called for
The 3/4 is the stud shank diameter, the parenthesised count is how many, and the twelve-inch pitch spaces them down the flange as composite shear connectors.
And what it does not say
- No length is given, so each weld runs the full length of the joint.
- Nothing sits above the reference line, so the far face of the joint stays bare.
- There is no circle at the elbow, so the weld does not continue around the joint.
Example 2: Small studs in a tight pattern
TitleSmall studs in a tight patternRefStud weldEx2 / 2Reads as
Attach eight 1/4 diameter studs on three-inch centres to the arrow-side face.
Which mark says so
- stud symbolBelow the reference lineA stud weld on the arrow side of the joint
- 1/4Left of the symbolSize of each weld - diameter for a spot, width for a seam
- -3Right of the length on the symbolPitch - centre to centre spacing of an intermittent weld
- (8)In parentheses beside the symbolHow many welds are called for
The symbol sits below the reference line because a stud is always welded to the surface the arrow touches, and the count and pitch define the row on that face.
And what it does not say
- No length is given, so each weld runs the full length of the joint.
- Nothing sits above the reference line, so the far face of the joint stays bare.
- There is no circle at the elbow, so the weld does not continue around the joint.
Common mistakes
- Drawing or reading the stud symbol on the other side of the reference line, which has no meaning here.
- Treating the diameter to the left as a weld size rather than the stud's shank diameter.
- Ignoring the collar of expelled metal when judging whether the weld went down properly.
- Laying out studs by eye when a pitch is given, which throws off the whole connector spacing.