Free original practice, with instant explanations. Study the reference below or start the 15-question welding symbols test. Every drawing is an inline SVG built by our code from simple geometry.
Learning aid only. Check against your code edition, procedure and the responsible inspector/engineer. Schematic marks omit production dimensions and joint details; they cannot approve a weld or establish acceptance criteria.
Practice shape recognition and placement. These generated questions are not exam items. Tab to the answer group, use arrow keys to choose, then check your answer.
Set 20261017 · 0 of 15 answered · 0 correct
Question 1 of 15
Welding symbols explained: the parts
The weld symbol is the small shape that names the weld. The complete welding symbol includes its reference line, arrow and any extra instructions. This page practices the single solid reference-line convention governed by AWS A2.4. Check which notation system your drawing uses.
Our schematic example: a fillet weld below the reference line.
Reference line
The horizontal anchor for the shape and its instructions.
Arrow
Identifies the joint or surface. Arrow side is relative to the joint it points to.
Tail
An optional fork for process, procedure or specification references.
Arrow side vs other side
Below the line means arrow side; above means other side. Marks on both sides call for both. Changing the arrow's direction does not reverse this convention.
In the example above, first follow the arrow to the joint. The triangle identifies a fillet weld. Its position below the line calls for the arrow side. A matching triangle above the line as well would call for fillet welds on both sides. These schematic exercises do not specify weld size.
No engineering calculation is needed to identify a symbol. The score uses percentage = correct answers ÷ 15 × 100, rounded to a whole percent. For example, 12 correct answers gives 12 ÷ 15 × 100 = 80%. Each question earns one point; this is not an exam pass prediction.
Printable welding symbols chart
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Fillet Gauge · Welding symbols chart
Original schematic drawings · 17 October 2026
Below = arrow side · Above = other side · Both = both sides. Centered spot/seam marks below have no side significance. Marks are schematic and not to scale.
Fillet weld
A right triangle identifies a fillet weld at a joint. Arrow side shown.
Square-groove weld
Two parallel strokes identify a square groove. Arrow side shown.
V-groove weld
Two sloping faces form the V-groove mark. Arrow side shown.
Bevel-groove weld
One straight face and one sloping face identify a bevel groove. Arrow side shown.
U-groove weld
A rounded bowl on a short stem identifies a U groove. Arrow side shown.
J-groove weld
One straight face and one curved face identify a J groove. Arrow side shown.
Plug / slot weld family
A rectangle is shared by plug and slot welds. Dimensions and the joint detail distinguish them. Arrow side shown.
Spot weld
A circle identifies a spot weld. Here it is centered: no side significance. No side significance shown.
Seam weld
A circle crossed by two parallel lines identifies a seam weld. Here it is centered. No side significance shown.
Back / backing weld
One unfilled semicircle. Back weld follows the groove weld; backing weld precedes it. Check the sequence note. Shown opposite a V groove; sequence unspecified.
Surfacing weld
Two adjacent arcs identify added surface material, such as buildup. Arrow-side placement only. Arrow side shown.
Edge weld
Three parallel strokes joined at their outer ends identify an edge weld, often on sheet edges. Arrow side shown.
Weld all around
A circle at the arrow junction extends the weld around the joint.
Field weld
A flag at the junction calls for welding at the installation site.
Melt-through
A filled semicircle opposite a groove calls for visible root reinforcement with complete penetration.
Flat / flush contour
A straight contour mark specifies the weld face profile; finish method is a separate instruction.
Convex contour
An outward curve specifies a raised weld face.
Concave contour
An inward curve specifies a hollowed weld face.
AWS A2.4 governs the conventions. Public educational reference: Open Oregon Educational Resources, Cameren Moran, Interpretation of Metal Fab Drawings (2017), chapters 4–10: openoregon.pressbooks.pub/weldsymbols/.
Check against your code edition, procedure and the responsible inspector/engineer. No standard text or figures reproduced.
Recognize the limits of the shape
The plug/slot rectangle names a family: a plug fills a round hole; a slot uses an elongated opening. Dimensions and a joint detail resolve which one is intended. It is not a fillet around a hole.
The unfilled back/backing semicircle needs a sequence note. A back weld is made after the groove weld; a backing weld is made before it. A backing weld is different from backing material. The reference shows this shared mark opposite a groove; the quiz does not ask you to infer the sequence from shape alone.
Spot and seam symbols can have different placements depending on the process and instructions. Our quiz uses only centered examples, with no side significance. Surfacing examples stay on the arrow side. For bevel and J grooves, the drawing may also identify which member is prepared with a broken arrow; these exercises ask only weld family and side.
Supplementary marks add instructions to a basic symbol. The all-around circle is at the arrow junction; a spot circle is along the reference line. A filled melt-through mark differs from the unfilled back/backing mark. Contour describes the finished face; a finishing-method instruction is separate.