Final thesis, elaborated within the master study in the field of Manufacturing technology, deals with analysis and solving of weld cracking problem in welds of anti-roll bar socket for passenger car. Sockets material is fine-grained low-alloy steel S420MC. For better understanding of the problem, a literary study has been elaborated, describing the issue. Next, an analysis of parts material and its weldability, has been conducted, according to ČSN EN 1011-2 standard. After an analysis of cracks and considering current conditions of sockets welding a series of experiments has been designed to evaluate impact of different process parameters on final weld quality. Experiments results have been used to compile a series of recommendations for adjustment of the welding process and to eliminate weld cracking. The results of the experiments were used as a basis for elaboration of WPS protocol.

The calculation of the loadbearing capacity of hollow section joints using the design formulas according to EN 1993-1-8 assumes full-strength welded connections if the non-linear stress distribution over the circumference is not covered by calculation. Sufficient ductility in the connections ensures a plastic redistribution capacity within each joint. In the case of hollow section structures made of high-strength steels, it becomes more difficult to meet the requirement for full-strength welds as the yield strength of the base material increases. This article begins with a summary of the current rules for the design and execution of welded hollow section joints. The softening behaviour of high-strength steels and the loadbearing capacity of welded connections with local softening in the HAZ are then discussed. That is followed by the presentation of the results from the AiF-FOSTA research project P1020 regarding the influence of manufacturing parameters on the properties of welded connections and the HAZ. The experimental test programme for single-sided welded T-connections and the parameter studies within the research project P1453 are also described. Finally, a design approach is presented to account for HAZ failure and hybrid failure modes of hollow section connections.