The theme of this work is "Application of SAW welding procedure in boiler construction" which is used in the thermal power plant. The introduction in the diploma thesis describes in detail the materials used in boiler construction, operating conditions and division of boilers. The general welding and SAW welding and SAW welding parameters are discussed in the following sections. The application of SAW welding is shown with the corresponding pictures of machines on which the welding of a fin-fin joint, a tube joints and welding during the production of membrane tube walls is performed. In the experimental part of this thesis, an example from the practice of welding a butt joint of tubes made of 13CrMo5-4 material by SAW method is shown, where the welding of the root pass was performed by GTAW method and filling with SAW method, where we had the possibility of applying the SMAW method. The test and heat treatment procedure for this weld is presented. The conclusion discusses the advantages and disadvantages of SAW welding, comparison with other processes and the importance of applying the SAW procedure in boiler construction.