AWS A2.4 weld symbols — Learn • Explore • Practice • Quiz
Welding symbols are the universal shorthand used on engineering drawings to communicate exactly where, how, and what type of weld is required on a fabricated joint. Standardised under AWS A2.4 (American Welding Society) and ISO 2553, these symbols eliminate ambiguity between the design engineer and the welder on the shop floor. This free online welding symbol trainer covers the 12 most important weld types across four categories: groove welds, fillet welds, plug & slot welds, and resistance (spot & seam) welds.
Every welding symbol is built on a reference line — a horizontal line from which all information hangs. An arrow connects the reference line to the joint where the weld is to be made. The weld type symbol is placed below the reference line for the arrow side (the side the arrow points to) and above for the other side. A forked tail on the opposite end can specify the welding process (e.g., GMAW, SMAW). Dimensions — weld size (left of the symbol) and length (right of the symbol) — complete the specification. Supplementary symbols indicate field welds (flag), weld-all-around (circle), and face contour (flush, convex, concave).
Groove welds include Square, V-Groove, Bevel, U-Groove, J-Groove, Flare V-Groove, and Flare Bevel. They are used for butt joints where full or partial penetration is required. The fillet weld — the most common weld type, accounting for roughly 80% of all welds — is used on T-joints, lap joints, and corner joints. Plug and slot welds join overlapping plates through circular or elongated holes. Spot and seam welds are resistance welds that fuse overlapping sheet metal without filler material.
Start in Learn mode to study the anatomy of a welding symbol with interactive part highlighting. Switch to Explore mode to browse all 12 weld types — see the AWS symbol on the reference line alongside the actual joint cross-section, and toggle between arrow side, other side, and both-sides placement. Practice mode presents random symbol identification challenges with instant feedback and score tracking. Finally, Quiz mode tests your knowledge with 5 randomised questions and a scored result panel.
This welding symbol trainer is designed for welding students, fabrication apprentices, mechanical engineering learners, CWI exam candidates (Certified Welding Inspector), NDT technicians, and workshop instructors who need a quick, visual way to teach or revise AWS welding symbols without needing a physical chart or textbook.