Build-up welding is a common repair technique for restoring worn pipe surfaces or building up undersized components. The number of passes directly influences productivity and quality, but many shops still rely on rule-of-thumb rather than systematic optimisation.
For a given bead width, the overlap ratio between adjacent beads determines surface smoothness and dilution control. A typical target is 30-50% overlap: too little leaves valleys that require extra fill passes; too much increases heat input and distortion. The pass count can be estimated by dividing the total build-up width by the effective bead width times (1 - overlap fraction).
Practical considerations include: welding position affects bead shape and width; travel speed and wire feed speed must be adjusted to maintain consistent bead geometry across passes; interpass temperature control is critical to avoid excessive heat buildup in multi-layer deposits.
A structured approach using a simple spreadsheet to calculate minimum passes for a given width, bead width, and overlap ratio can reduce trial runs by 20-30%. This saves consumables and cycle time while ensuring consistent quality.
How do you determine pass count for build-up welding in your shop?