WeldSymbols

AWS A2.4

Welding Symbols

A welding symbol is read from the reference line outward: the arrow points at the joint, a symbol below the line means weld the arrow side, above means the other side, and the shape names the weld type. All 11 AWS A2.4 weld symbols are below, each with its own drawing.

Type at least two characters. Press slash to focus this field.

Weld symbols

Fillet weld symbol AWS A2.4 fillet weld symbol: reference line, leader, arrowhead and weld symbol.

Fillet Weld

A right triangle with the perpendicular leg always drawn on the left

 V-groove weld symbol AWS A2.4 v-groove weld symbol: reference line, leader, arrowhead and weld symbol.

V-Groove Weld

A V opening away from the reference line

 Bevel-groove weld symbol AWS A2.4 bevel-groove weld symbol: reference line, leader, arrowhead and weld symbol.

Bevel-Groove Weld

A half-V: one vertical leg on the left, one angled leg on the right

 U-groove weld symbol AWS A2.4 u-groove weld symbol: reference line, leader, arrowhead and weld symbol.

U-Groove Weld

A U opening away from the reference line

 J-groove weld symbol AWS A2.4 j-groove weld symbol: reference line, leader, arrowhead and weld symbol.

J-Groove Weld

A half-U: one vertical leg and one curved leg

 Plug weld symbol AWS A2.4 plug weld symbol: reference line, leader, arrowhead and weld symbol.

Plug Weld

A rectangle on the reference line

 Slot weld symbol AWS A2.4 slot weld symbol: reference line, leader, arrowhead and weld symbol.

Slot Weld

A rectangle on the reference line, dimensioned as a slot

 Spot weld symbol AWS A2.4 spot weld symbol: reference line, leader, arrowhead and weld symbol.

Spot Weld

A circle on the reference line

 Seam weld symbol AWS A2.4 seam weld symbol: reference line, leader, arrowhead and weld symbol.

Seam Weld

A circle with a horizontal line through it

 Back or backing weld symbol AWS A2.4 back or backing weld symbol: reference line, leader, arrowhead and weld symbol.

Back or Backing Weld

A semicircle on the opposite side of the reference line from the groove symbol

 Surfacing weld symbol AWS A2.4 surfacing weld symbol: reference line, leader, arrowhead and weld symbol.

Surfacing Weld

Two semicircular arcs side by side on the arrow side of the reference line

Anatomy of a welding symbol

Everything on a welding symbol hangs off the reference line. The guide to reading welding symbols works through a complete example.

Reference lineThe horizontal backbone of every welding symbol. Everything else attaches to it, and it is always drawn horizontal on the drawing.
ArrowThe leader and arrowhead that connect the reference line to the joint. The side of the joint the arrow touches is the arrow side.
Weld symbolThe shape that says which kind of weld is required — triangle for a fillet, V for a V-groove, circle for a spot, and so on.
Arrow side (below the line)A weld symbol drawn below the reference line calls for a weld on the side of the joint the arrow points to. This is the convention that catches people out most often.
Other side (above the line)A weld symbol drawn above the reference line calls for a weld on the far side of the joint.
Both sidesSymbols drawn above and below the reference line call for welds on both sides of the joint.
TailAn optional fork at the far end of the reference line, used to reference a specification, process or procedure such as GMAW or a WPS number.
DimensionsSize is placed to the left of the weld symbol; length and pitch are placed to the right.

Supplementary symbols

These modify the instruction rather than naming the weld itself.

SymbolShapeMeaning
Weld-all-aroundA circle drawn at the junction of the arrow and the reference line.The weld continues completely around the joint.
Field weldA flag on a staff at the junction of the arrow and reference line.The weld is made in the field or on site rather than in the shop.
Melt-throughA filled semicircle on the side of the reference line opposite the weld symbol.Complete joint penetration with visible root reinforcement on the far side, welded from one side only.
Consumable insertA square placed on the opposite side of the reference line from the groove symbol.A consumable insert ring is used in the root of the joint.
Backing or spacerA rectangle on the opposite side of the reference line from the groove symbol.Backing material or a spacer is used in the joint.
Flush or flat contourA straight line across the face of the weld symbol.The finished weld face is to be flush with the base metal.
Convex contourAn arc bulging away from the weld symbol.The finished weld face is to be convex.
Concave contourAn arc curving into the weld symbol.The finished weld face is to be concave.
Finish methodA letter placed with the contour symbol — C chipping, G grinding, M machining, R rolling, H hammering.How the specified contour is to be produced.

Weld symbol shapes and placement conventions follow AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination. Descriptions are written from the standard's conventions; the standard itself is the governing document.