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AWS A2.4 §7.2.10 · Curved + Flat Surface

Flare-Bevel Groove Weld Symbol

How to read a flare-bevel groove weld symbol — C-shape for a curved member against a flat plate. Broken arrow points to the curved member. Groove weld size from outside surface.

Flare-Bevel Groove Weld Symbol — Anatomy
D(S) C-shape = 1 curved mbr
Single flare-bevel symbol
broken arrow = curved mbr
Broken arrow convention
double = both sides
Double flare-bevel
Inherent geometry (A2.4 §7.2.10.4): Groove depth D is the distance from the point of tangency to the top of the member. D is not mandatory on the symbol because the radius of the curved member determines it inherently. Omitting both D and S implies complete joint penetration (§7.2.10.6).
How to Read

Flare-Bevel Symbol Dimensions

The flare-bevel groove symbol has a single C-shape (one curved line, one straight vertical line) on the reference line. This represents a round or curved member meeting a flat plate surface, creating a natural groove that is filled with weld metal.

What the Joint Looks Like

Per A2.4 §7.2.10.1, a flare-bevel groove weld joint is formed between a member with a curved surface and a surface of a planar member. A round bar or tube welded to flat plate is the most common application. No machining is required — the groove shape comes from the member geometry.

Broken Arrow

Per A2.4 §7.1.3.1, a broken arrow is used for single-flare-bevel groove welds to identify which member has the curved surface. The break in the arrow points to the curved member. Without the broken arrow (straight arrow), either member may have the desired edge shape.

Groove Weld Size (S)

Per A2.4 §7.2.10.5, S is measured from the outside surface of the curved member. Place S in parentheses to the left of the symbol for PJP welds.

Groove Depth (D)

Per A2.4 §7.2.10.4, D is the distance from the point of tangency to the top of the member and is not required on the symbol. When both D and S are omitted, complete joint penetration is specified (§7.2.10.6).

Combination joints: Per A2.4 §7.2.10.3, a flare-bevel groove can combine with another groove type (such as a bevel-groove) to form a combination groove weld. This applies when the curved member's geometry alone does not provide enough penetration.
CJP vs. PJP

Complete and Partial Joint Penetration

Per A2.4 §7.2.10.1, flare-bevel groove weld joints may be designated as either partial joint penetration (PJP) or complete joint penetration (CJP) welds.

Partial Joint Penetration (PJP)

Specify groove weld size S in parentheses to the left of the symbol. S is measured from the outside surface of the curved member. Groove depth D may also be shown if needed for clarity.

Complete Joint Penetration (CJP)

Per A2.4 §7.2.10.6, omitting both D and S indicates complete joint penetration — the same convention used for all other CJP groove welds. This requires the weld to extend fully through the joint cross-section.

Practical note: Most flare-bevel groove welds in practice are PJP because achieving true CJP through the natural flare geometry is difficult without additional preparation. When CJP is required, the joint may be detailed as a combination groove weld (A2.4 §7.2.10.3).
Common Questions

Flare-Bevel Groove Weld Symbol FAQ

What is a flare-bevel groove weld?
A flare-bevel groove weld joint is formed between a member with a curved surface and a surface of a planar member, per AWS A2.4 §7.2.10.1. A common example is a round bar or tube welded to a flat plate — the curved surface of the round member and the flat plate surface create a natural groove that is filled with weld metal. No machining is needed. The symbol looks like a C or reversed-J shape on the reference line.
Does the flare-bevel groove weld use a broken arrow?
Yes. Per AWS A2.4 §7.1.3.1, a broken arrow is used for single-flare-bevel groove welds to specify which member has the curved surface (the edge shape that forms the groove). The broken arrow points to the member with the curved surface. This is the same convention used for bevel-groove and J-groove welds — the break in the arrow identifies which member gets the specified edge shape.
How is groove weld size measured for a flare-bevel groove weld?
Per AWS A2.4 §7.2.10.5, the groove weld size S is measured from the outside surface of the curved member. The groove depth D is the distance from the point of tangency to the top of the member (§7.2.10.4). D is not mandatory on the symbol because it is an inherent feature of the joint — the radius of the curved member determines it automatically. Omitting both D and S indicates complete joint penetration, per §7.2.10.6.
Can a flare-bevel groove weld be complete joint penetration?
Yes. Per AWS A2.4 §7.2.10.1, flare-bevel groove weld joints may be designated as partial joint penetration or complete joint penetration welds. Per §7.2.10.6, omitting both D and S from the symbol indicates complete joint penetration — the same convention as other groove welds. A flare-bevel groove can also form a combination groove weld with another groove type (§7.2.10.3), such as a flare-bevel combined with a bevel-groove.
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