The main goal of this bachelor thesis was to characterize the welded joint between the pipe and the plate of austenitic stainless steel graded X1CrNiMoCuN20-18-7. Classification of stainless steels as their properties and characteristics were described in the theoretical part of the thesis. The weldeability of austenitic stainless steels was described in more detail. In the experimental part of the paper, metallographic sample preparation was carried out in order to analyse the macrostructure and microstructure along with microhardness HV0.2 test in the base material, heat-affected zone, and weld metal. The analysis of the macrostructure showed incomplete weld root and asymmetrical shape of weld within the allowed limits. The microstructure analysis showed that the base materials of the plate and pipe have a typical austenitic microstructure with a delta-ferrite content of less than 6%. The fusion line on the side of the plate is clearly expressed, the heat-affected zone is narrow, and the microstructure is austenitic with slightly larger grains. The fusion line on the pipe side is also noticeable, but the microstructure of the heat-affected zone is not visible. The weld metal microstructure is a typical as-cast dendritic structure with clearly defined passages. The highest values of microhardness HV0.2 were measured in the weld metal, slightly lower in the heat-affected zone and the lowest in the base material of the plate. The measured microhardness at the root of the weld is higher than in the middle and weld face.