Influence of the cooling time on the mechanical properties of welded HSS-joints

In Memoriam of Prof. Dr. Bernt Johansson
The influence of the cooling time t8/5 has been examined as part of the ongoing AiF-FOSTA P1020 research project for the development of a new design approach for welded joints on high-strength steels. Four thermomechanically rolled and quenched steel grades were investigated. The temperature-time course of a MAG welding process was thermo-physically simulated in a quenching and deformation dilatometer to evaluate the material behaviour. Subsequently, the influence of the cooling time on the mechanical properties of welds was examined using a flat tensile test specimen with a centric hole. The results of the examinations form the scientific basis for a significant improvement of the current execution rules for welded joints between high-strength steels taking into account mismatching of base material and filler metal.