Onystchuk О. Estimation of descriptions of pipelines materials by internal corrosion of oil-and-gas pipelines.

It is shown, that one of the reasons of corrosion damage of pipelines is the presence of hydrogen sulphide and also carbon dioxide and low-molecular carboxylic acids admixtures in the products of deposits, which under high temperature and pressure conditions causes intensive internal corrosion. A new parameter for estimation of corrosion processes is proposed and substantiated. This is certain characteristic value of concentration of harmful admixtures, and on reaching it abrupt growth of corrosion rate of 17Г1С steel occurs. Тhe operating ageing of steel reduces corrosion resistance of pipelines. It is determined, that electrode potentials and microhardness in different areas of the welded connection substantially depend on structural-chemical hheterogenic and heat treatment conditions. All explored types of heat treatment result in the increase of stress corrosion stability of the welded connections; here the annealing and high-temperature tempering normalization had the most substantial influenсе.