용접후방의 냉각에 의한 용접 잔류응력과 변형 저감 효과에 관한 연구

Abstract

The problems created by welding in industrial site are deformation and residual stress. They not only cause the nonlinear deformation but also have an influence on weldability, moreover the problems are harmful that cracks could be created when using structure. At industrial sites, some postprocesses which take a lot of time and cost are conducted to fix the deformation and residual stress. Researches about deformation of welding and residual stress should be carried out to develop high value products. In this study, research of decreasing the deformation and residual stress during welding process by a way of Heat sink with numerical analysis when welding a thin plate would be done. With a way of Heat Sink, the parameters would be changed variously to deduct an optimum condition which has the lowest deformation and residual stress. Afterwards, the numerical values of residual stress with optimum condition of Heat Sink Welding and other existing way of welding would be compared to find out the level of reduction. As a result, the deformation for the existing welding is 2.6mm and that for the Heat Sink Welding is 0.02mm. In comparison with the existing welding, the result shows about 99% of reduction of deformation with Heat Sink Welding. In the case of residual stress, generally it is decreased more with Heat Sink Welding than the other way. Judging from the result, by applying a cooling source to the rear of a heat source of welding, the existence of the best condition that doesn’t occur the deformation is confirmed.