COMPLEX EVALUATION OF STRUCTURE AND MATERIAL PROPERTIES OF SELECTED WELDING JOINTS

The National Action Plan for the Development of Nuclear Energy in the Czech Republic envisages the preparation for the construction of two new blocks of the nuclear power plant in the location of Dukovany and the location of Temelín. Although the final supplier of these units is not clear yet, there are good prospects that some components could be produced by the local producers. The paper presents the principal results of development and verification of production technology of weld joints of pressure vessels components for primary circuits of the nuclear power plants of MIR 1200 type. Attention was focused to the influence of welding technology SAW and SMAW including post weld heat treatment on the final mechanical and fracture properties of welded joints of large forgings. Homogeneous weld joints were made of 10GN2MFA low-alloy steel while heterogeneous weldment was prepared from 10GN2MFA and 08CH18N10T stainless steel. The welded joints were subjected to a comprehensive evaluation of the material properties, especially the evaluation of macro and microstructure, tensile test and impact bending test as well as unconventional mechanical properties such as initial value of the J-integral, the stress intensity factor and low cycle fatigue limit. The effect of welding technology on the transition temperature (Tk0) of the weld joint was evaluated, too.