One of the highest costs in steel manufacturing comes from the welding workshop. Welding is a very sensitive but important part of the construction industry. Avoiding distortions of the welded parts becomes very important for the steel producer. Furthermore, residual stresses are known to have a significant influence in the design of members subjected to failure through plastic-elastic buckling as well as fatigue. Thus it is crucial to be able to estimate the expected distortions and to compensate for them from the design phase. The purpose of the study is to investigate the heat distribution in welded plates and to evaluate the induced residual stresses and distortions resulted from welding. For this purpose a heat-transfer and a coupled thermal-mechanical analysis are made. The outcome of the study is expected to lead to better welding practices for steels in the construction industry.