Welding Symbols Chart

Identify common AWS weld symbols and decode arrow side, dimensions, contours, and drawing notes.

Welding Symbols Chart — AWS A2.4 Quick Reference

AWS side rule: below = arrow side above = other side both = symbols above and below

Common AWS A2.4:2020 welding and supplementary symbol reference; symbols are independently drawn for identification and interpretation.
Symbol & name	Meaning & drawing notes
Fillet weld	A triangular weld symbol used for fillet welds at intersecting surfaces. Details Size is normally placed to the left of the symbol; length and pitch, when used, are placed to the right. Position above or below the reference line gives the side under AWS conventions.
Square groove	A groove weld with essentially square joint preparation. Details Use the drawing dimensions and joint detail to determine root opening, penetration requirements, and any other preparation information.
V-groove	A groove weld where both members are prepared to form a V. Details Groove angle, root opening, depth of preparation, and weld size may be specified around the symbol as required by the drawing.
Bevel groove	A groove weld where one member is square and the other is beveled. Details A break in the arrow can be used when it is necessary to identify which member receives the preparation.
U-groove	A groove weld with curved preparation on both members, forming a U profile. Details The symbol identifies the groove form; actual preparation dimensions come from the welding symbol, detail, specification, or WPS.
J-groove	A groove weld with a square edge on one member and a curved J preparation on the other. Details As with a bevel groove, the drawing must identify the prepared member when that distinction matters.
Flare-V-groove	A groove formed by two curved surfaces, such as adjoining rounded members. Details AWS A2.4:2020 includes revised guidance for flare-groove usage; do not infer weld size from the graphic alone.
Flare-bevel-groove	A groove formed between a curved surface and a substantially planar surface. Details The joint geometry and required weld dimensions must be taken from the drawing or governing welding documentation.
Plug weld	A weld made in a hole in one member to join it to another member. Details In AWS A2.4:2020 the diameter mark is no longer part of the basic plug weld symbol; the diameter symbol is still used when designating the plug dimension.
Slot weld	A weld made in an elongated hole or slot in one member to join it to another. Details Slot dimensions, orientation, spacing, and extent are defined by the complete welding symbol and drawing information.
Spot / projection	A circular basic symbol used for spot or projection weld notation, with process/context completing the meaning. Details AWS A2.4:2020 uses the value to the left to designate weld size; required strength is specified by note rather than using that left-side value as strength.
Seam weld	A seam-weld symbol used where a continuous or intermittent seam is specified. Details Size, length, pitch, number, and process information are supplied by the rest of the welding symbol as applicable.
Stud weld	Identifies a stud-weld requirement. Details Stud weld location significance is arrow-side only in the conventional AWS chart presentation; quantity or spacing is conveyed with the complete callout when needed.
Surfacing weld	Specifies weld metal deposited on a surface for buildup, overlay, wear resistance, or similar surfacing purposes. Details The required thickness, area, process, material, and finishing requirements come from the full drawing or welding documentation.
Edge weld	Identifies an edge weld made on the edges of adjoining or adjacent members. Details Length, extent, size, and any contour requirements must be read from the full symbol and drawing detail.
Weld all around	A circle at the arrow/reference-line junction indicates welding around the joint as defined by the drawing geometry. Details It does not mean “weld everything everywhere.” The symbol applies to the joint indicated by the arrow and the extent rules of the governing drawing.
Field weld	A flag at the arrow/reference-line junction indicates a weld to be made in the field rather than at the initial shop or fabrication location. Details The symbol communicates location of execution; it does not by itself define process, procedure, or acceptance criteria.
Flush / flat contour	A straight contour mark specifies a flush/flat final contour in the context allowed by the standard. Details AWS A2.4:2020 distinguishes terminology/application: the flat contour symbol is limited to fillet welds, while flush is used for other welds such as groove, plug, and slot welds.
Convex contour	Specifies a convex final weld contour. Details A finishing-method letter may accompany the contour symbol when the method is specifically required; otherwise do not infer a particular finishing process from the contour mark alone.
Concave contour	Specifies a concave final weld contour where applicable. Details The contour symbol communicates the required final profile; it does not itself choose the welding or finishing method.

Scope: 20 common AWS A2.4:2020 weld and supplementary symbols are shown here for fast identification. AWS A2.4 also addresses additional cases such as back/backing welds, melt-through, consumable inserts, spacers, intermittent and combination welds, multiple reference lines, brazing, and NDE symbols; use the governing standard for those cases.

The symbol graphics are original Turn2Engineering drawings. Basic geometry was cross-checked against the official AWS A2.4:2007 welding-symbol chart, then the AWS A2.4:2020 publisher preview and revision notes were used to confirm current edition scope and documented changes such as plug-symbol and contour usage.

Print scope: anatomy, the currently visible symbol rows, interpretation notes, and source basis.

Reference actions

How to Read a Welding Symbol

AWS A2.4:2020 convention: information below the reference line applies to the arrow side; information above applies to the other side. Always confirm the standard named on the drawing.

Arrow side

Weld symbol below the reference line.

Other side

Weld symbol above the reference line.

Both sides

Weld symbols appear above and below the line.

How Do You Read a Welding Symbol?

Find the arrow and joint. The arrow points to the joint or feature the welding information applies to.
Check the side. Under AWS A2.4, a weld symbol below the reference line is arrow side; above the line is other side.
Identify the weld type. The basic weld symbol identifies fillet, groove, spot, seam, plug/slot, edge, stud, surfacing, or another supported weld type.
Read dimensions around the symbol. Size or depth information is generally placed to the left; length and pitch are generally placed to the right when those dimensions apply.
Read supplementary information. Contour, field-weld, weld-all-around, tail notes, process references, and other drawing instructions can change how the callout is interpreted.

Weld symbol vs. welding symbol

The weld symbol is the graphic that identifies the weld type. The welding symbol is the complete system built around the reference line and arrow, including dimensions and supplementary information.

Length and pitch

For intermittent weld notation, pitch is center-to-center spacing, not simply the open gap between adjacent weld segments.

AWS vs. ISO Welding Symbols: Check the Drawing Standard First

AWS A2.4 and ISO 2553 are not interchangeable drawing systems. The primary chart above uses the AWS A2.4:2020 placement convention. ISO 2553:2019 recognizes two systems: System A uses a dual reference line, while System B uses a single reference line. Confirm the standard identified on the project drawing before decoding side significance.

AWS A2.4:2020

For the common AWS convention, below the line is arrow side and above the line is other side.

ISO 2553:2019

ISO 2553 includes System A (dual reference line) and System B (single reference line); use the system actually specified on the drawing.

Current edition note: ISO 2553:2019 remains the published fifth edition. ISO/DIS 2553 is an Edition 6 draft under development and should not be treated as the final replacement until ISO publishes it.

Worked Example: Decode One AWS-Style Fillet Callout

Illustrative notation example only; the numbers are not a welding recommendation.

Fillet symbol below the line: the weld applies to the arrow side under AWS placement rules.

6 to the left: the drawing is specifying a weld-size value in the drawing’s stated unit system.

50–100 to the right: this illustrates a length–pitch style callout, with pitch interpreted as center-to-center spacing.

The actual unit system, joint design, process, WPS, acceptance criteria, and code requirements must come from the governing project documents.

Sources and Reference Scope

This page is an AWS-first quick-reference for drawing identification. The graphics are independently redrawn: basic symbol geometry was cross-checked against the official AWS A2.4:2007 chart, while the AWS A2.4:2020 publisher material controls current scope and documented edition changes. ISO material is included only to establish the standards boundary.

American Welding Society — AWS A2.4:2020, Standard Symbols for Welding, Brazing, and Nondestructive Examination. Controlling edition/source listing for welding-symbol construction and interpretation.
American Welding Society — AWS A3.0M/A3.0:2025, Standard Welding Terms and Definitions. Current AWS terminology reference for welding and allied processes.
AWS A2.4:2020 publisher preview. Foreword and table of contents confirm the 2020 edition changes and locate Clauses 4, 6, 7–15 and the associated symbol/application figures.
American Welding Society — AWS A2.4:2007 Welding Symbol Chart. Used only as a historical geometry cross-check for basic recognizable symbols; superseded by the 2020 edition for current interpretation.
American Welding Society — “How to Correctly Use Welding Symbols for Slotted Hollow Structural Steel Members”. Confirms Clause 6.1 arrow-side placement below the reference line.
ISO 2553:2019, Welding and allied processes — Symbolic representation on drawings — Welded joints. Published Edition 5; describes Systems A and B.
ISO/DIS 2553. Edition 6 draft under development; not treated as the current final standard.

Source check: September 26, 2026
Primary convention: AWS A2.4:2020
ISO boundary: ISO 2553:2019 published; ISO/DIS 2553 draft
Excluded: Complete NDE/brazing symbol systems, code acceptance limits, WPS qualification, proprietary standard figures, and exhaustive combination examples

Copyright note: this page does not reproduce AWS or ISO standard pages or commercial charts. The SVG graphics are independently drawn reference illustrations intended to help identify common symbol concepts.

Common Welding Symbol Questions

What does a triangle mean on a welding symbol?

A right-triangle weld symbol is the common fillet weld symbol. Under AWS conventions, its position above or below the reference line tells you whether it applies to the other side or arrow side of the joint.

Does a symbol below the line mean arrow side?

Yes for AWS A2.4 notation: information applicable to the arrow side is placed below the reference line. Do not automatically apply that rule to a drawing governed by a different symbol system.

What does the circle at the arrow and reference line mean?

The weld-all-around supplementary symbol is a circle at the arrow/reference-line junction. Read it with the joint geometry and the rest of the drawing to determine the intended extent.

What does the flag on a welding symbol mean?

The flag is the field-weld symbol. It identifies a weld to be made in the field rather than at the initial fabrication location.

Does a welding symbol tell me what welding procedure to use?

Not by itself. A welding symbol communicates drawing requirements, but the governing WPS, code, project specification, material requirements, and qualified procedure still control how the weld is produced and accepted.

Need electrode classification and position information instead of drawing notation? Use the Welding Rod Chart. Return to the Charts & Tables hub for other engineering references.