Weld Tabella dei Simboli PDF
Free Stampabile AWS A2.4:2020 reference — all Saldatura Tipi, symbol anatomy, and finishing codes. Use your browser to print or save as PDF.
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Section 1Symbol Anatomy
1
Reference Line
A horizontal line that anchors every welding symbol. All other elements attach to it. Always drawn horizontally regardless of joint orientation.
2
Arrow
Connects the reference line to the joint. The side where the arrow points is the arrow side; the opposite side is the other side (A2.4 §6.1.1). For bevel/J-groove, a break in the arrow indicates the prepared member (A2.4 §6.4).
3
Weld Symbol
Graphic indicating weld type (triangle = fillet, V = groove, etc.). Position relative to reference line determines side: below = arrow side, above = other side, both = both sides.
4
Dimensions
Size to the left of the Simbolo di Saldatura. Length and pitch to the right. Depth/throat in parentheses.
5
Tail
Forked end — contains process (SMAW, FCAW), WPS number, or Specifica reference. Omit if unused.
6
Weld-All-Around
Open circle at the reference/arrow junction — weld must continue completely around the joint perimeter. Distinct from the field weld flag (solid filled triangle at the same junction).
7
Field Weld Flag
Solid filled triangle at the reference/arrow junction — weld to be made in the field (at the erection site), not in the shop. The flag may point in either direction per A2.4 §6.9.
8
Contour Symbol
Same side as the weld symbol, on its outer face — flush, flat, convex (outward arc), or concave (inward arc) — A2.4 lists flush and flat as distinct contour types. Arrow side = below reference line; other side = above. Paired with finishing letter.
Section 2Weld Symbol Reference
| Weld Type | Symbol | Size Notation | Common Applications |
|---|---|---|---|
| Fillet | Leg Dimensione left of symbol (e.g. 6 for 6mm) |
T-joints, lap joints, corner joints — most common weld type | |
| Square Groove | (S) — weld size in parens; groove depth D not applicable to square grooves (§7.2.6) |
Butt joints, full/partial penetration | |
| V-Groove | D(S) — groove depth D, weld size (S) in parens |
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 weld size as D(S) |
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 | |
| Flare-Bevel Groove | Effective throat noted | Round bar or tube to flat surface — one curved member | |
| Plug | Hole diameter left, depth inside symbol, pitch right | Lap joints where fillet access is limited | |
| Slot | Width left, length-pitch right, depth inside symbol | Elongated plug weld for wider lap joints | |
| 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 | Size left, pitch right, count in parens below — arrow-side only | Shear connectors in composite construction | |
| Back / Backing | Same symbol for both. Removable backing: add R inside symbol. Distinction is welding sequence: a backing weld is placed before the Saldatura a Scanalatura, a back weld after. | CJP groove back-gouged and back-welded | |
| Edge | Size (height of deposit) left of symbol | Flanged butt joints in sheet metal, light gauge | |
| Melt-Through | Height of reinforcement left of symbol | CJP welds requiring visible root reinforcement |
Supplementary Symbols
| Symbol | Graphic | Placement | Meaning |
|---|---|---|---|
| Field Weld | Flag at reference line / arrow junction | Weld to be made in the field (erection site), not in the shop | |
| Weld-All-Around | Circle at reference line / arrow junction | Weld extends completely around the joint perimeter |
Section 3Size Notation Quick Reference
Fillet Weld Notation
6Leg size — 6mm equal-leg fillet both sides when on both sides of reference line6×8Unequal 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.6left +50-150rightIntermittent — leg size (6mm) to left of symbol; length–pitch (50mm weld, 150mm c/c) to right. Not a single hyphenated string.D(S)Groove notation — groove depth D without parentheses, weld size/effective throat S in parentheses. Per A2.4§7.2.1.
Groove Weld Notation
D(S)D = groove depth (preparation depth). (S) = weld size/effective throat (design dimension)12(10)12mm groove depth, 10mm effective throat — D without parentheses, (S) in parenthesesRRoot opening value — often shown in tail or drawing note, not symbolαGroove 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 spacing50-15050mm long welds, 150mm apart (center). Net gap = 100mmstaggeredIntermittent symbols offset on arrow side vs other side = chain or staggered
Tail Reference Codes
SMAWShielded Metal Saldatura ad Arco (stick)FCAWFlux Cored Arc WeldingGMAWGas Metal Arc Welding (MIG)GTAWGas Tungsten Arc Welding (TIG)WPS-01Refers to specific Specifica di Procedura di Saldatura document
Section 4Finishing & Contour Codes
G
Grinding
Angle grinder or belt grinder. Achieves flush or specified contour. Most common field method.
M
Machining
Mill, lathe, or surface grinder. High-tolerance finish. Used in precision machined weldments.
C
Chipping
Pneumatic chipping hammer. Removes slag or excess material. Rarely specified for final finish.
H
Hammering
Peening. Induces compressive stress in surface. Used in fatigue-critical applications.
R
Rolling
Roller burnishing. Smooths and work-hardens surface. Used in pressure vessels and pipe.
P
Planishing
Planishing roll or burnishing. Smooths weld surface by controlled plastic deformation. Uncommon in structural work.
U
Unspecified
Method not specified — contractor may use any suitable method to achieve the required contour.
Flat Contour (flush)
Weld face finished flush with Metallo Base 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 Metallo di Saldatura at the face.
Concave Contour
Weld face has inward curvature (hollow profile). Symbol: arc curving toward reference line. Sometimes specified for fillet welds to control convexity on non-fatigue members.
Frequently AskedQuestions
Is there a free Tabella Simboli di Saldatura PDF?
Yes. Click Print / Save PDF on this page or use your browser's print function. No registration required.
What Norma do weld symbol charts follow?
In North America, Simboli di Saldatura 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, and the Middle East use AWS A2.4. Australia uses AS 1101.3 (aligned with ISO). 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 groove depth (D) appears without parentheses, and the weld size/effective throat (S) appears in parentheses — written as D(S) per A2.4. 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 Processo di Saldatura (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.
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 alongside the solid reference line to indicate the other side. Groove weld dimension placement also differs between the two standards. Most global projects specify which standard governs on the drawing title block.
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