Weld Symbol Reference

Triangular weld symbol for a fillet weld at a lap, T, corner or similar joint.

Leg size, length, pitch and contour/finish symbols are added around the reference line.

Square-butt groove weld where the joint faces are not beveled.

Root opening, groove depth and backing details are called out separately when required.

Double-beveled preparation forming a V-shaped groove.

Groove angle, root opening, root face, depth of preparation and weld size may all be specified.

Single beveled member against an unbeveled mating member.

Arrow side matters because the arrow can identify which member receives the bevel.

Curved groove preparation with U-shaped sides.

Radius and root dimensions are drawing- or procedure-specific; do not infer prep from symbol alone.

Single curved J-shaped groove preparation.

As with bevel groove symbols, arrow-side/member selection can be part of the callout.

Groove formed between two curved surfaces, such as two round bars or tubes.

Effective throat and actual achievable size depend on the joint geometry and applicable standard.

Groove formed by one curved surface against a flat or prepared member.

Check the governing detail; flare-groove callouts are commonly misread in fabrication drawings.

Weld made through a round hole or slot in one member to join it to another.

Diameter or slot dimensions, depth of filling, count and pitch are separate callout fields.

Resistance spot, projection or similar localized weld callout.

Process, size, pitch, number of spots and member side convention depend on the standard and note set.

Resistance seam or continuous seam-type weld callout.

Length, pitch and intermittent/continuous requirements must be read with the rest of the drawing.

Build-up, hardfacing or deposited weld metal applied to a surface.

Layer count, thickness, contour, material and process usually live in tail notes or procedure notes.

Weld placed on the back side of a groove joint or a backing-related callout.

The difference between back weld and backing weld depends on sequence and the governing standard wording.

Weld at the edge of one or more members.

Read member thickness and fit-up notes carefully before treating edge welds like fillet welds.

Stud or fastener welded to a surface.

Stud size, count, spacing, process and inspection are normally controlled by notes and project specs.

Circle at the arrow/reference-line junction meaning the weld continues all around the joint.

Do not use it when access or geometry prevents a continuous all-around weld.

Flag at the arrow/reference-line junction meaning the weld is made in the field.

Field welds still need process, access, fit-up, inspection and weather/worksite controls.

Root-side reinforcement or visible melt-through requirement.

Acceptance depends on code, procedure, backing/back-gouging details and inspection method.

Contour mark calling for approximately flush finished weld surface.

Finish method letters or tail notes can specify grinding, machining, chipping or other treatment.

Contour mark indicating a convex finished weld surface.

Convexity limits and acceptance are not implied by the icon alone.

Contour mark indicating a concave finished weld surface.

Read with finish method, procedure and acceptance criteria.

Dimension format for intermittent weld segment length and center-to-center pitch.

Staggered intermittent welds and chain intermittent welds are shown differently by placement.

Tail at the end of the reference line for process, specification, WPS, NDE or other notes.

If no reference is needed, the tail may be omitted depending on the drawing standard.