Consumable insert
Applied to joint
Supplementary symbol applied to fillet weld
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Description
A supplementary symbol indicating that a consumable insert ring or strip is placed in the root of the joint before welding. The insert melts and becomes part of the root pass weld metal, ensuring consistent root fusion and profile.
In plain English
A pre-formed ring or strip of filler metal is placed in the root gap before welding. When you strike the root pass, the insert melts and fuses into the weld, giving you a consistent, controlled root bead. Very common on pipe welding -- particularly stainless steel and high-alloy pipe where root quality is critical. The insert is matched to the base metal and filler metal composition. The symbol is an open square on the root side. Saves time on fit-up and gives a much more consistent root than relying on the welder alone.
Symbol position
Open square on the root side of the weld symbol.
Size notation
Insert classification/type noted in the tail. No separate dimension -- the insert size is determined by the joint design.
Common uses
- High-purity stainless steel pipe welding (food, pharma, semiconductor)
- Nuclear piping root passes
- High-alloy pipe where root quality is critical
- Automated orbital pipe welding
