TWI Frequently asked questions
General rules for preventing distortion are:
- keep the weld (fillet) to the minimum specified size
- use balanced welding about the neutral axis
- keep the time between runs to a minimum
In the absence of restraint, angular distortion in both fillet and butt joints will be a function of the joint geometry, weld size and the number of runs for a given cross section. Angular distortion (measured in degrees) as afunction of the number of runs for a 10mm leg length fillet weld is shown in Fig.1.
Fig.1. Angular distortion, α, as a function of number of runs, N. If possible, balanced welding around the neutral axis should be done, for example on double sided fillet joints, by two people welding simultaneously. In butt joints, the run order may be crucial in that balanced welding can be usedto correct angular distortion as it develops. Copyright by TWI, 1999
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