Assembly of components before welding, setting root opening, alignment, bevel condition and tack welds to the WPS and drawing. A fitter's work largely decides whether a welder can make a sound weld: inconsistent gaps, hi-lo and dirty bevels cause burn-through, incomplete penetration and distortion. Inspectors often check fit-up before welding starts, especially on CJP joints.
Fit-up on spool 14 is all over the place, gap goes from nothing to a quarter, send it back to the fitter.
Fix fit-up with the fitter, not the welder; fighting a bad gap with the arc all day is the slowest and costliest repair there is.
Also heard as
- fitup
- fitting
Related terms
Root opening
The gap between members at the root of a joint, set during fit-up before welding.
Hi-lo
Shop name for misalignment between two pipe or plate edges, where one sits higher than the other.
Dog
A small steel lug tacked to a part so a wedge or bolt can pull pieces into alignment during fit-up.
Tack weld
A short weld placed during fit-up to hold parts in line until the full-length welds go in.
Land
Shop word for the flat root face left at the bottom of a bevel, called the root face in codes.