HELP TO CONTROL DISTORTION

Adopting the following assembly techniques will help to control distortion:

• Pre-set parts so that welding distortion will achieve overall alignment and dimensional control with the minimum of residual stress
• Pre-bend joint edges to counteract distortion and achieve alignment and dimensional control with minimum residual stress.
• Apply restraint during welding by using jigs and fixtures, flexible clamps, strongbacks and tack welding but consider the risk of cracking which can be quite significant, especially for fully welded strongbacks.
• Use an approved procedure for welding and removal of welds for restraint techniques which may need preheat to avoid forming imperfections in the component surface.