Fillet weld
A right triangle on the reference line: a fillet weld, the triangular weld that joins two surfaces meeting at about a right angle.
This explains what a symbol specifies on a drawing. It isn't welding instruction, and a drawing's own notes and the governing code take precedence.
How to read it
A fillet weld has a roughly triangular cross section. It joins two surfaces at approximately right angles to each other, as in a lap, tee or corner joint.
The symbol is drawn with its vertical leg to the left of its slanted leg, whichever way the joint faces. The same rule holds for the bevel, J-groove and flare-bevel symbols. Below the reference line, the symbol calls for a fillet weld on the arrow side of the joint; above it, on the other side; on both sides of the line, fillet welds on both sides of the joint.
Contours
A contour symbol beside the fillet symbol says how the weld's face is to be formed: flush, convex or concave.
More welding symbols
Sources
- Steelworker, Volume 1, NAVEDTRA 14250, 1996, Naval Education and Training Professional Development and Technology Center, U.S. Navy (Internet Archive), Chapter 3, Drawings and specifications
- Welding Theory and Application, TM 9-237, 1967, Department of the Army (Internet Archive), Glossary
- Scheme of symbols for welding, IS 813:1986, Bureau of Indian Standards (Internet Archive, Public.Resource.Org), Tables 1 and 2
Last reviewed September 25, 2026 by Rory Hansen. How we research