What is the difference between AWS A2.4 and ISO 2553 weld symbols?

AWS A2.4 (used in North America) places the weld symbol below the reference line for the arrow side and above for the other side. ISO 2553 (used in Europe and internationally) uses a dashed identification line below the reference line for the other side, and no dashed line when specifying the arrow side. Groove weld symbols also differ: AWS uses a V for a V-groove; ISO uses the same V but positions dimensions differently. Most global projects now specify which standard applies on the drawing title block.

Weld Symbol Chart PDF — Printable AWS A2.4 Reference

Q: Is there a free weld symbol chart PDF?

Yes. This page contains a complete weld symbol reference per AWS A2.4:2020 that you can print to PDF using your browser's Print function (Ctrl+P or Cmd+P → Save as PDF). It includes all standard weld types, symbol anatomy, size notation positions, and finishing/contour codes — the same information as a physical reference card.

Q: What standard do weld symbol charts follow?

In North America, weld symbols follow AWS A2.4 (Standard Symbols for Welding, Brazing, and Nondestructive Examination), currently in its 2020 edition. Internationally, ISO 2553:2019 is used. The two standards are similar but differ in arrow/other-side conventions and some symbol geometries. Most fabrication drawings in the US, Canada, Australia, and the Middle East use AWS A2.4.

Q: How do I read the size dimensions on a weld symbol?

For fillet welds, the number to the left of the weld symbol is the leg size (e.g., 6 for a 6mm fillet). For groove welds, the number in parentheses is the groove depth (S) and the number outside is the effective throat (E). Numbers appear on the arrow side or other side of the reference line depending on which joint face the weld applies to. Length and pitch for intermittent welds appear to the right of the symbol as length-pitch (e.g., 50-150).

Q: What do the letters at the tail of a weld symbol mean?

The tail of a welding symbol (the forked end of the reference line) contains specification, process, or other reference information. Common examples: 'SMAW' (Shielded Metal Arc Welding), 'FCAW' (Flux Cored Arc Welding), 'GTAW' (TIG), a WPS number like 'WPS-001', or a note like 'SEE DWG A-3'. If no tail information is needed, the tail is omitted entirely.

Save as PDF: Press Ctrl+P (Windows/Linux) or Cmd+P (Mac) → select Save as PDF. The page re-renders print-optimised — white background, all tables intact.

Section 1Symbol Anatomy

Reference Line Horizontal baseline — all symbol elements attach to it. Arrow side = below, other side = above.

Arrow Points to the joint location. For bevel/J-groove, a break in the arrow indicates the prepared member.

Weld Symbol Graphic indicating weld type (triangle = fillet, V = groove, etc.). Placed below or above the line.

Dimensions Size to the left of the weld symbol. Length and pitch to the right. Depth/throat in parentheses.

Tail Forked end — contains process (SMAW, FCAW), WPS number, or specification reference. Omit if unused.

Weld-All-Around Circle at reference/arrow junction — weld must continue completely around the joint.

Field Weld Flag Filled triangle at reference/arrow junction — weld to be made in the field, not in the shop.

Contour Symbol Same side as the weld symbol, on its outer face — flat (flush), outward arc (convex), or inward arc (concave). Arrow side = below reference line; other side = above. Paired with finishing letter.

Section 2Weld Symbol Reference

Weld Type	Size Notation	Common Applications
Fillet	Leg size left of symbol (e.g. `6` for 6mm)	T-joints, lap joints, corner joints — most common weld type
Square Groove	`(S)E` — groove depth in parens, throat outside	Butt joints, full/partial penetration
V-Groove	`(S)E` — groove depth in parens, throat outside	Butt joints, full/partial penetration
Bevel Groove	Arrow break indicates prepared member	One-sided prep butt joints, T-joints with PJP
U-Groove	Groove depth and throat as `(S)E`	Thick section butt joints — reduces weld volume vs V
J-Groove	Arrow break indicates prepared member	One-sided prep, thick plates — half U-groove
Flare-V Groove	Effective throat noted	Round bar or tube to plate, formed sections
Plug / Slot	Hole diameter left, depth in parens, pitch right	Lap joints where fillet access is limited
Spot / Projection	Diameter left, pitch right, number of spots in parens	Resistance welding, sheet metal
Seam	Width left, length-pitch right	Continuous resistance or EBW seam
Surfacing	Height of deposit left, no groove prep	Hard-facing, build-up, overlay
Stud	Stud size, pitch, and quantity	Shear connectors in composite construction
Back / Backing	Same symbol for both. Removable backing: add R inside symbol. Distinction between back weld and backing weld is made in the tail — not by a letter code on the symbol.	CJP groove back-gouged and back-welded

Section 3Size Notation Quick Reference

Fillet Weld Notation

6Leg size — 6mm equal-leg fillet both sides when on both sides of reference line
6×8Unequal fillet — both sizes appear to the left as S1×S2. Orientation not specified by the symbol; a drawing detail shows which leg goes on which member.
6 left + 50-150 rightIntermittent — leg size (6mm) to left of symbol; length–pitch (50mm weld, 150mm c/c) to right. Not a single hyphenated string.
(S)EGroove notation — groove depth S in parentheses, effective throat E outside. Parentheses indicate depth of preparation, not fillet throat.

Groove Weld Notation

(S)ES = groove depth (preparation depth). E = effective throat (design dimension)
(12)1012mm groove depth, 10mm effective throat — indicates root gap or land
RRoot opening value — often shown in tail or drawing note, not symbol
αGroove angle — typically shown in tail as a degree value (e.g. 45°)

Intermittent Weld Notation

length-pitchWritten right of symbol. Length = each weld run. Pitch = center-to-center spacing
50-15050mm long welds, 150mm apart (center). Net gap = 100mm
staggeredIntermittent symbols offset on arrow side vs other side = chain or staggered

Tail Reference Codes

SMAWShielded Metal Arc Welding (stick)
FCAWFlux Cored Arc Welding
GMAWGas Metal Arc Welding (MIG)
GTAWGas Tungsten Arc Welding (TIG)
WPS-01Refers to specific Welding Procedure Specification document

Section 4Finishing & Contour Codes

Grinding

Angle grinder or belt grinder. Achieves flush or specified contour. Most common field method.

Machining

Mill, lathe, or surface grinder. High-tolerance finish. Used in precision machined weldments.

Chipping

Pneumatic chipping hammer. Removes slag or excess material. Rarely specified for final finish.

Hammering

Peening. Induces compressive stress in surface. Used in fatigue-critical applications.

Rolling

Roller burnishing. Smooths and work-hardens surface. Used in pressure vessels and pipe.

Planishing

Planishing roll or burnishing. Smooths weld surface by controlled plastic deformation. Uncommon in structural work.

Unspecified

Method not specified — contractor may use any suitable method to achieve the required contour.

Flat Contour (flush)

Weld face finished flush with base metal surface. Symbol: straight line above the weld symbol. Typically paired with G, M, or C finish method.

Convex Contour

Weld face has outward curvature above the base metal. Symbol: arc curving away from reference line. Provides extra weld metal at the face.

Concave Contour

Weld face has inward curvature (hollow profile). Symbol: arc curving toward reference line. Used for fatigue applications — reduces stress concentration.

Frequently AskedQuestions

Is there a free weld symbol chart PDF?

Yes. Press Ctrl+P (Windows/Linux) or Cmd+P (Mac) on this page and select Save as PDF. The page re-renders with a white background, all tables and SVG symbols intact — suitable for printing and field reference. No registration required.

What standard do weld symbol charts follow?

In North America, weld symbols follow AWS A2.4 (currently A2.4:2020). In Europe and internationally, ISO 2553:2019 applies. The two are similar but differ in arrow-side/other-side conventions. Most drawings in the US, Canada, Australia, and the Middle East use AWS A2.4. Always check the drawing title block — it should state which standard governs.

How do I read the size dimensions on a weld symbol?

For fillet welds: the number to the left of the triangle symbol is the leg size. For groove welds: the number in parentheses is the groove depth (S), the number outside is the effective throat (E). Numbers on intermittent welds to the right of the symbol read as length–pitch (e.g. 50-150 means 50mm long welds on a 150mm center-to-center pitch).

What do the letters at the tail of a weld symbol mean?

The tail (the forked end of the reference line) contains a specification, process code, or reference. Common examples: a welding process (SMAW, FCAW, GTAW), a WPS number (WPS-001), or a drawing note reference (SEE DWG A-3). If no tail information is needed, the tail is omitted entirely. Per A2.4, the tail is used only when additional information is required that cannot otherwise be shown on the symbol.

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