Abstract: Bolts calculation techniques for flange joints of pump, working in high-temperature medium is presented. The Malinin flow theory is used. The obtained relations allow to determine a stress drop in the part in a pie-set time term of assign an initial stress which in a specified time will drop to a certain value, or to determine a period or time in the course of which a delay force (an initial stress) will drop to a pie-set value. The numerical examples axe presented.