Mathematical Simulation of Microstructural Phase Transformations in the Course of Welding Heating for the Case of Cladding of Protective Layer in the WWER-1000 Reactor Vessel

By using the developed finite-element models, we perform numerical investigation of nonstationary temperature fields and kinetics microstructural phase transformations in base material WWER -1000 reactor vessel (15Kh2NMFА steel) under conditions submerged-arc cladding protective anticorrosion layers austenitic materials. We comparative analysis results simulation obtained by two methods prediction decomposition austenite process cooling. The first method is based on application regression equations characteristic cooling time Δ t8/5. second diagrams isothermal austenite, Avrami equation, Koistinen–Marburger equation. As a result cladding, obtain bainite-martensite composition heat-affected zone vessel, which confirmed dilatometric metallography.