Canadian Weld Symbols — AWS Standard Reference for CSA W59 Fabrication
Complete reference for standard weld symbols per AWS A2.4 as adopted by CSA W59 for Canadian structural steel fabrication. Covers the welding symbol system, fillet/groove/plug/slot weld symbols, supplementary symbols, and typical Canadian drawing examples.
Quick access: CSA weld capacity → | CSA W59 welding procedure → | Weld inspection →
AWS/CSA Welding Symbol System
The welding symbol in Canadian practice follows AWS A2.4, consisting of:
- Reference line (horizontal) — mandatory for all symbols
- Arrow — points to the joint location
- Tail — contains welding process, electrode, and other specifications
- Weld symbols — placed above or below the reference line
Symbol Placement Rule
| Location | Meaning |
|---|---|
| Symbol below reference line | Arrow side of the joint |
| Symbol above reference line | Other side of the joint |
| Symbol on both sides | Welds on both sides |
| Symbol on reference line (field weld) | Weld made in the field |
Common Weld Symbols
Fillet Weld Symbol
| Symbol | Description | Application |
|---|---|---|
| ▐ (right triangle) | Fillet weld | Most common — lap, T, corner joints |
Fillet weld callout example: 8 mm fillet weld, 100 mm long, 4 places (E48XX): Symbol: 8 × 100 (4) — E48XX
The weld leg size is placed to the left of the symbol, length to the right.
Groove Weld Symbols
| Symbol | Name | Typical Use |
|---|---|---|
| V | Single-V groove | Butt joints, full penetration, plates > 12 mm |
| Λ | Double-V groove | Butt joints, thick plates from both sides |
| Y | Single-bevel groove | T-joints requiring full penetration |
| U | Single-U groove | Heavy plate butt joints, improves root access |
| I | Square groove | Thin plates < 6 mm, light fabrication |
| J | Single-J groove | Heavy T-joints, one side only |
Plug and Slot Weld Symbols
| Symbol | Description | Application |
|---|---|---|
| ▭ | Plug weld | Round holes filled with weld |
| ▭ | Slot weld | Elongated holes filled with weld |
Supplementary Symbols
| Symbol | Meaning | CSA W59 Application |
|---|---|---|
| ○ (above tail) | Weld all around | Continuous perimeter weld |
| ▾ (flag at break) | Field weld | Site welding (not shop) |
| ▵ (below tail) | Field weld (alternate) | Site welding symbol |
| √ (on reference line) | Melt-through | Full joint penetration (FJP) |
| ∼ (on reference line) | Contour — flat | Flush weld surface |
| ∼ | Contour — convex | Standard fillet weld profile |
| ∼ | Contour — concave | Special, ground smooth |
| G | Grind finish | Grind weld flush |
| C | Chip finish | Chipping hammer finish |
| M | Machined finish | Machine flush |
Complete Welding Symbol Example
8
─────▐─────
E48XX│ [tail] │200
│ │
Interpreting the symbol:
- Arrow side: 8 mm fillet weld
- Other side: no weld
- Length: 200 mm
- Electrode: E48XX
- Process: specified in tail (e.g., SMAW)
Full Penetration Groove Weld
12
───── V ─────
FJP│ [tail] │
- Single-V groove, 12 mm root opening
- FJP: Full joint penetration
- Back-gouging required for full penetration
Canadian Drawing Conventions
Per CSA W59, Canadian structural steel drawings typically:
- Use metric dimensions — weld leg sizes in mm (6, 8, 10, 12, 16 mm typical)
- Specify electrode classification in the tail (E48XX, E49S-6, E550T-5)
- Indicate weld all around for perimeter welds on gusset plates
- Use field weld symbol for site connections
- Indicate process when not SMAW (e.g., GMAW, FCAW in tail)
Typical Drawing Callouts
| Connection Type | Symbol Callout | Interpretation |
|---|---|---|
| Beam web to girder web | 8 × 75 — E48XX | 8 mm fillet, 75 mm long, 2 welds (one each side of web) |
| Column base plate | 10 (continuous) — E48XX | 10 mm fillet, all around, continuous |
| Gusset plate to beam | 8 — E48XX ○ | 8 mm fillet, weld all around |
| Field splice | 6 × 150 ▾ — E49S-6 | 6 mm fillet, 150 mm long, field weld, GMAW |
Weld Quality Symbols
Per CSA W59 and AWS D1.1:
| Symbol | Quality Requirement | Inspection Level |
|---|---|---|
| None specified | Standard commercial quality | Visual (VT) only unless specified |
| CVN | Charpy V-notch impact required | Additional UT per AASHTO/AWS |
| UT | Ultrasonic testing required | Full volumetric NDT per CSA W59 |
| RT | Radiographic testing required | Radiography per CSA W59 |
| MT | Magnetic particle testing | Surface crack detection |
| PT | Dye penetrant testing | Surface crack detection (non-ferrous) |
Worked Example — Reading a Weld Symbol
Interpret this symbol callout:
10×100(4)
───────▐─────────
E48XX │ ○ ▾ │
Interpretation:
- Fillet weld symbol (▐) below reference line → arrow side
- Leg size = 10 mm
- Length = 100 mm each segment
- (4) = 4 intermittent weld segments
- ○ (circle at arrow tail break) = weld all around (perimeter)
- ▾ (flag) = field weld
- Tail: E48XX electrode
- The weld is a 10 mm × 100 mm intermittent fillet, 4 segments, all around the perimeter of the joint, to be welded in the field using E48XX electrodes.
Frequently Asked Questions
What do the numbers on a fillet weld symbol mean in Canadian practice? The number to the left of the fillet symbol is the weld leg size in mm (e.g., 8 = 8 mm leg). The number to the right is the weld segment length (e.g., 100 = 100 mm long). If there is a number in parentheses, it indicates the number of intermittent weld segments. The electrode is specified in the tail (e.g., E48XX).
What is the difference between field weld and shop weld symbols? A field weld symbol has a flag at the intersection of the arrow and reference line. A shop weld has no flag. This distinction is critical in Canadian fabrication: shop welds are made under controlled conditions in the fabricator's facility, while field welds are made on-site where conditions (wind, temperature, access) are less controlled and typically require stricter quality control.
How is weld all around indicated on a Canadian steel drawing? The weld all around symbol is a circle at the intersection of the arrow and reference line (on the arrow side of the reference line). This indicates the weld extends continuously along the entire perimeter of the joint. For gusset plates, this is common — the gusset is welded all around to the beam or column.
What does FJP (full joint penetration) mean on a groove weld symbol? FJP indicates the weld metal extends through the full thickness of the joint. For complete joint penetration (CJP) groove welds, the weld symbol shows the groove type (V, bevel, U, J) with no size designation — the full thickness is implied. The backing bar (if any) and back-gouging requirements are specified in the tail.
Related Pages
- CSA Weld Capacity — Fillet Weld Table
- CSA W59 Welding Procedure Specifications
- CSA Weld Inspection — Visual, UT, MPI
- Canadian CSA Weld Sizes — Minimum Weld Table
- CSA Weld Electrode Selection Guide
- Welded Connection Calculator
- All Canadian References
This page is for educational reference. Weld symbols per AWS A2.4/A2.4M as adopted by CSA W59. Verify symbol interpretation against project welding specification. Results are PRELIMINARY — NOT FOR CONSTRUCTION without independent PE/SE verification.
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