Gembara O. Assessment of hydrogen damage of bimetals under heat variation

The theses deal with the problems of assessing hydrogen damages of bimetallic structural elements under the effects of temperature variation. The model is based on the equation of hydrogen uptake in the crack under nonstationary variation of the temperature field and an equation of such crack propagation. Using this model a method for assessing the durability of bimetallic structural elements under hydrogen effect and heat variation as well as a criterion of the optimal material choice in them have been developed. Hydrogen redistribution in a bimetallic wall of the shell of petrolium hydrocracking reactor and formation of overequilibrium hydrogen oversaturations there were investigated in the theses. The influence of the kinetics of heat variation, solubility coefficients and hydrogen diffusion in the reactor materials and their geometrical characteristics on the maximum value of hydrogen concentration in a wall and pressure level in the subsurface crack have been studied. The kinetic of such crack pro pagation due to of temperature variation from 723 K to ambient temperature has been studied theoretically.