Surfacing Weld Symbol
The surfacing weld symbol is two small arcs side by side, like a scalloped bead, drawn below the reference line. It calls for weld metal laid on a surface to build it up, hard-face it or clad it, rather than to join parts. It is always on the arrow side, the size on the left is the minimum thickness of the build-up, and the area is shown on the drawing.
How to read the surfacing weld symbol
Surfacing deposits beads side by side over an area: to restore a worn shaft, hard-face a bucket tooth or clad a vessel with corrosion-resistant alloy. The two arcs on the symbol look like the edge of those overlapping beads.
There is no joint, so there is no other side: the arrow points at the surface to build up, and the symbol always goes below the reference line. The extent and direction of the beads come from the drawing and notes.
What each dimension position means
| Position | Meaning |
|---|---|
| Left (S) | Minimum thickness of the surfacing build-up. No value means no specific thickness. |
| Area and direction | Shown by the drawing: dimensions of the area, and a note on bead direction if it matters. |
| Tail | Process, filler alloy, or a specification such as a hardfacing grade. |
Example callout, read aloud
“Build up the surface the arrow points to with at least 1/8 inch of weld metal, using gas metal arc welding with ER70S-6 wire.”
Example: reading the callout piece by piece
- Surfacing symbol below the line: build up the arrow-side surface.
- 1/8 left: the finished build-up must be at least 1/8 inch thick.
- Tail: process and filler for the deposit.
Result: Build up the surface the arrow points to with at least 1/8 inch of weld metal, using gas metal arc welding with ER70S-6 wire.
When it is used
- Rebuilding worn shafts, rolls and wear pads before machining back to size.
- Hardfacing digging teeth, crusher parts and chutes against abrasion.
- Cladding carbon steel with stainless or nickel alloy for corrosion resistance.
Common mistakes
- Drawing surfacing above the line. Surfacing is arrow side only.
- Reading the size as maximum thickness. It is the minimum build-up. Allow extra for machining.
- Leaving the area undefined. Dimension the surface to be built up on the drawing.
- Using it for a joint. Surfacing does not join parts; use a fillet or groove symbol.
Related weld symbols
- Back and backing weld: The back/backing semicircle is a single arc; surfacing is two.
- Fillet weld: Fillet welds join parts; surfacing builds up one surface.
- Plug and slot weld: Plug welds fill holes rather than covering a surface.
- Edge weld: Edge welds join sheet edges.
- Field weld: Field repairs of worn parts often combine surfacing with the field flag.
Every weld symbol page: welding symbols chart
Calculators and further reading
Frequently asked questions
Why is surfacing always on the arrow side?
There is no joint, only a surface. The arrow points at that surface, so the symbol is always below the line.
What does the number on a surfacing symbol mean?
The minimum thickness of the build-up.
Is hardfacing shown with the surfacing symbol?
Yes. Hardfacing, build-up and cladding all use the surfacing symbol, with the alloy or specification in the tail.
How is the area to surface shown?
By dimensions on the drawing view, with any bead direction given in a note.
Sources
- AWS A2.4 Standard Symbols for Welding, Brazing, and Nondestructive Examination, American Welding Society
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