○ Weld all around
Weld all around · Soldadura en plano · ISO 1101 + ASME Y14.5
Example in plan
How to interpret it
On the drawing, “△ a 4 with weld-all-around circle” states a weld all around requirement.
What controls
A circle placed at the junction of the arrow and the reference line that extends the specified weld to the entire contour of the joint, not just the segment the arrow points at. It applies both to closed round contours (a tube on a plate) and to contours that change plane (a rectangular gusset), and the weld size and type are the same along the whole path unless the drawing says otherwise. It does not by itself imply leak tightness: that is a separate requirement that must be called out explicitly.
How to verify
Visual inspection of the entire perimeter, using a mirror or borescope where there is no direct line of sight, checking that no segment is left unwelded and that the start/stop overlap is fused. Size is checked with a gauge at several points spread around the contour, including the hardest-to-reach areas, which are the ones that usually come out undersize. If leak tightness is also required, it is closed out with a leak test, not with visual inspection.
Common mistakes when interpreting it
- Welding only the segment the arrow points at: the circle requires the whole contour, including the hidden sides.
- Interpreting it as a leak-tightness requirement: welding all around does not guarantee the joint will not leak unless someone tests it.
- Leaving the closing tie-in without overlap, which is where most lack-of-fusion defects appear on closed contours.
How to get it in the workshop / if it comes out of tolerance
It is one of the callouts most often missed on the shop floor, because the circle is small and the welder only sees the accessible face. Before starting, plan how the part will be turned: a closed contour forces awkward positions and requires overlapping the start with the end. If a segment cannot be reached, that is raised before welding, not silently skipped.
The weak point is almost always the tie-in where the weld closes on itself: grind down the end crater and overlap a short length before breaking the arc. At the corners of rectangular contours, do not start or stop right at the corner; carry through and tie in on the straight section. If a segment comes out short because of access, rethink the assembly sequence so it is welded before the assembly is closed up.
Related symbols
Other symbols in Flat welding
Related tools
ISO fits
Calculates indicative ISO 286 tolerances for shaft and hole, H7/g6, H7/h6, H7/k6 and H7/p6 fits with clearance, transition and interference graph.
Inspection Plans
Upload a plan, extract dimensions and GD&T with AI and export your inspection guideline in PDF or CSV.
Shop trigonometry
Workshop trigonometry: right triangle, C chamfer, Z countersink, sine bar, taper and polar→X/Y for CNC operators.