Creep of degraded 2.25Cr-Mo steel in hydrogen

The results of creep tests of 2.25 Cr-Mo steel are used to show that the secondary creep rate in a gaseous hydrogen is higher than in air both for the metal in the intact state and after its operation in the technological processes of hydrocracking of petroleum. This means, first, that the properties of the metal guaranteeing its serviceability in the initial period of its service are exhausted in the process of operation and, second, that hydrogen affects both the degradation and creep processes. Indeed, hydrogen intensifies the diffusion processes and, hence, accelerates the degradation of the metal and facilitates creep.