Reduction of Manufacturing Distortion in Arc Welded Ship Panels Using Thermal Tensioning
Large sheet or thin plate steel structures invariably suffer from distortion especially when fabricated using an arc welding process. The cost of reworking in shipbuilding is high. Low-stress no-distortion (LSND) welding has been demonstrated to effectively prevent distortion. The technique has been show to work well by rapidly cooling the weld with atomized water or liquid CO2 immediately after solidification. However, this can be expensive and difficult to apply in the fabrication of large structures. In this work, only a thermal tensioning technique is presented. The technique controls distortion by applying thermal stresses in front of the weld pool to counteract the stresses induced in the structure by welding. A combination of finite element modeling and experimentation has been used to find a thermal tensioning arrangement that reduces distortion by 50% in 4 mm butt welded steel plates using arc welding.