The results of investigations of nitrogen and oxygen regenerators metal after long
period of exploitation with analysis of change of mechanical properties and structural state
under the influence of the low temperatures and pulsating load are given in this paper. It is
shown the destruction of 12X18H10T steel occurs because of the undiffusion processes of
transition of austenite info martensite and of cracking on the borders of grains. The
destruction process of apparatus proceeds most intensively on the welded joints where the
most structural non-uniformity with presence of welding defects and residual stresses take
place