GaugePass

Weld symbol

Flare bevel groove weld symbol

One straight member against one rounded one. The symbol shows a vertical leg and a single outward curve, and the groove is formed by the radius of the curved part rather than by any cutting.

1/4 (3/16)
The symbol as it appears on the drawing
arrowarrow sideother side
The joint it produces, in cross-section

Reads as: Arrow side: flare-bevel-groove weld, 1/4 size, 3/16 effective throat.

How to read it

The flare bevel symbol is half a flare-V: a perpendicular leg on the left representing the flat member and a single bowed curve on the right representing the rounded one. It describes the very common situation where a tube, a bar, or the formed corner of a section sits against a plate and their contact line forms a natural groove on each side.

As with the flare-V there is no cut and therefore no angle. The dimensions that matter are how deep the weld fills the natural groove and what effective throat that fill is credited with. Both sit to the left of the symbol, with the throat in parentheses after the depth when the two differ, and they differ often because the curved face pinches the groove near the root.

Tube-to-plate connections are where this symbol lives, and they are also where its reading matters most. The available groove depth is limited by the tube's corner radius, so a designer cannot simply ask for more throat by writing a bigger number: the geometry caps it. When a drawing calls for more than the radius can give, that is a conflict to raise before welding, not a target to chase with extra weld metal.

A flare bevel is frequently combined with a fillet on the same joint, with the groove filling the natural pocket and the fillet building the transition onto the flat member. When the symbol shows both, read them as one combined weld with two dimensions rather than as two independent welds on the same line.

Where each dimension goes

Depth of fill (left of the symbol)
How far into the natural groove formed by the radius the weld metal reaches.
Effective throat (in parentheses)
The throat the joint is designed around, capped by the rounded member's radius.
Length and pitch (right of the symbol)
Run length and spacing where the connection is welded intermittently along the tube.
Side of the reference line
Which side of the rounded member is welded. Both sides are commonly called out on a tube-to-plate joint.

Worked examples

Flare bevel on both sides of a tube

5/165/16

“Weld the natural groove on both sides of the tube, 5/16 deep each side.”

The curved symbol appears above and below the reference line, so both contact lines where the tube meets the plate are welded, each filled to its own stated depth.

Flare bevel combined with a fillet

3/161/4 (3/16)

“Fill the flare groove 1/4 deep and add a 3/16 fillet over it on the same side.”

Two symbols on the same side of the line describe one combined weld: the groove fills the pocket formed by the radius and the fillet builds the transition onto the flat member.

Common mistakes

  • Treating the flare bevel as a fillet and measuring a leg instead of a groove depth.
  • Chasing an effective throat the tube's corner radius physically cannot provide.
  • Missing the flat member's identity because the symbol's vertical leg is always drawn on the left.
  • Welding only one side of a tube-to-plate joint when the symbol shows the curve above and below the line.

Typical joints

Tube to plate connectionsRound bar to flat barFormed section corner to plateHollow structural section branch joints

Related symbols

Flare V-grooveTwo outward-bowing curves mean the groove is formed by the natural radius of two rounded members set together — no cutting involved, since the parts themselves create the vee.Bevel grooveHalf a vee — one vertical leg and one sloped face — means only one member is prepared. A broken arrow points at the member that gets the bevel, because the symbol alone cannot say.Fillet weldThe right triangle on the reference line calls for a fillet weld. The number to its left is the leg size, and the side of the line it sits on tells you which face of the joint gets welded.PJP groove weldA groove weld deliberately not carried through the full thickness. Numbers to the left of the symbol give the depth of preparation and, in parentheses, the effective throat the design relies on.

Practise reading welds, not just symbols

The drawing tells you what the weld should be. The gauge trainer is where you find out whether you can tell what it actually is.

Open the gauge trainer