Chuchman M. Нydrogenation and fracture resistance of pipe steel in hydrogen sulfide environments under static and cyclic stresses

Object of study: Corrosion-mechanical destruction of pipe steels and their welded joints in hydrogen sulfide environments. Purpose of work - establish the susceptibility to corrosion of steel pipe and mechanical destruction by static and cyclic symmetric and asymmetric loads in hydrogen sulfide environments and the impact on it of corrosion and hydrogen factors. The thesis is devoted to the influence of cyclic symmetric and asymmetric loads on the workability of pipe steels used in the oil and gas and oil refining industry. It is shown that the high resistance of steel to hydrogen sulfide stress corrosion cracking is not indicative of their high endurance for corrosion fatigue. It is shown that under the prevailing influence on the destruction resistance of the hydrogen factor on the susceptibility to hydrogen sulphide cracking of 20, 30CrMo pipe steel mainly has the number of mobile - diffusion, hydrogen and under the cyclic stress has a significant impact has the hydrogen of higher energy connection to metal. For example of 17Mn1Si steel shown that in aqueous solutions based on CH3COOH and NaCl under hydrogen sulfide saturation the concentration of hydrogen in the steel reaches maximum values of ~ 25 ... 32 ppm and is independent of the pH and corrosion rate. It is shown that in chloride - acetate environments saturated with hydrogen sulfide fraction of absorbed hydrogen from commonly selected by corrosion of 17Mn1Si steel is not more than 20%.