Influence of the Structural Features of Steels of Casing Pipes on their Mechanical Properties and Hydrogen Brittleness

Materials Science - We analyze the mechanical properties of steels of casing pipes of different strength classes and reveal an abnormally lower brittle-fracture resistance of a steel of lower...     

Analysis of the Stressed State of a Pipe of Gas Pipeline with Hydrogen-Induced Macrodefect

Materials Science - The long-term operation of gas mains may lead to the appearance of large-scale delamination inside the pipe wall under the conditions of its hydrogenation from the inner...     

Corrosion and stress-corrosion cracking of exploited storage tank steel

We study the corrosion resistance of St3S steel under loading and its susceptibility to corrosion and hydrogen-induced cracking in bottom water. Sections of a tank are distinguished according to the character of the media interacting with the metal of the inner surface in the process of operation. It is shown that bottom water is characterized by high levels of corrosion activity and that the degrees of in-service degradation of different sections of the tank are different. The worst corrosion and stress-corrosion resistance are exhibited by steel operating in contact with bottom water. Significant levels of plastic strains intensify the process of corrosion in steel and make the rates of corrosion in different sections of the tank closer to each other. The in-service degradation of steel can not only intensify the process of corrosion of the inner surface of the tank but also promote the brittle fracture of the material characterized by the elevated susceptibility to hydrogen-induced cracking.Published in Fizyko-Khimichna Mekhanika Materialiv, Vol. 40, No. 3, pp. 113–117, May–June, 2004.     

Corrosion and electrochemical properties of the steel of exploited oil tanks in bottom water

We have detected a distinction in the corrosion and electrochemical behavior of St3sp steel of different parts of an oil storage tank in under-product water of different oil refineries depending on preliminary contact between the metal and working media of different corrosiveness. Due to long-term contact of the steel with a corrosive working medium (under-product or condensed water), its corrosion resistance decreases substantially. We have established that a medium with an oil-water interface has the greatest corrosiveness, and oil-water emulsion has the lowest. The intensity of electrochemical processes is higher on the steel of those domains of the oil storage which contacted with under-product or condensed water as compared with the metal contacted with oil. The least mineralized under-product water is also the least corrosive. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 44, No. 1, pp. 104–108, January–February, 2008.