In order to create light weight structures in industry not only the application of high strength steels with yield strengths above 700 MPa may be used, but also the topology optimization of the design space. Cutting, metal forming and welding are manufacturing technologies which are often used to profile optimized construction elements. The results of these procedures are complex structures of high stiffness. New joining technologies as well as specific knowledge of temperature dependent material properties lead to increasing accurate design requirements in welding techniques. To calculate the fatigue behaviour of welded connections, local stress approaches are commonly used. Based on the virtual component geometry, local effective notch stresses were calculated and assigned to the overall structure. Manufacturing factors like residual stresses, phase transformation effects and welding parameters are currently not considered in the engineering standards. From a number of welding experiments energy per unit length, welding velocity and topographical formation of fusion zone were derived and transmitted to a coupled time- temperature dependent simulation model. Material and welding process parameters determine the local stresses numerically and provide the basement of the subsequent damage calculation. In the present work the residual stresses due to the welding process are implemented as mean stresses and after an operating load, the local damage of the structure was calculated by the use of FEMFAT, a lifetime calculation software tool. Expected component damage and location of technical crack initiation were compared to structural testing results.