The main function of a welding sequence is to control distortion due primarily to the effects of welding heat. In general, a large input of heat in a short time tends to produce the greatest distortion. Therefore, it is always advisable, for large joints, to weld in stages, with sufficient time between each stage to assure complete dis- persal of heat, except for heat needed to satisfy interpass temperature requirements. Equally important, and perhaps more efficient from the erector’s viewpoint, are those methods that balance the heat input in such a manner that the distortional effects tend to cancel out.