Mathematical Modeling of the Influence of Hydrogen on the Corrosion Activity of Metal Structures
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MATHEMATICAL MODELING OF THE INFLUENCE OF HYDROGEN ON THE CORROSION ACTIVITY OF METAL STRUCTURES W.-G. Song,1 O. V. Hembara,2, 3 and Ya. I. Sapuzhak2
UDC 620.197.5: 669.788
On the basis of the well-known theoretical concepts and some experimentally substantiated hypotheses, we propose a mathematical model aimed at description of the effect of diffusion-mobile hydrogen on the corrosion of pipe materials of crucial metal structures. The influence of hydrogenation of the metal on the corrosion rate of heat-exchange equipment is quantitatively evaluated. Keywords: hydrogenation, corrosion rate, hydrogen concentration.
Introduction Corrosion-induced defects often serve as a cause of destruction of materials of the crucial equipment in various branches of industry, such as the power industry, chemistry, petrochemistry, and transport and also in the industrial and main pipelines, bridges, harbor, and ship structures, etc. [1, 2]. These defects develop according to various mechanisms of local corrosion affected, in particular, by the hydrogenation of the metal. The results of model experiments [3–8] demonstrate that hydrogen sorbed by the metal may significantly accelerate the dissolution of iron and promote the development of local corrosion sites: pits and corrosion-induced cracks. Therefore, it is necessary to study the hydrogenation of the metal and its influence on the strength and serviceability of structural elements. Analysis of Recent Studies and Results In the available literature, one can find the description of numerous failures of various structural elements of the equipment that are environmentally hazardous and operate in contact with hydrogen-containing media [9– 12]. It was discovered that, as a result of the long-term operation of oil pipelines and oil tanks, the electrochemical characteristics of steels significantly deteriorate. Moreover, both the corrosion resistance of the metal in the bulk of the pipe and tank walls and its resistances to brittle fracture and corrosion or hydrogen-induced cracking become lower under the aggressive action of oil-water media. An important role played by hydrogenation in the process of degradation of steels under the operating conditions was established in [1, 2]. This is observed in the form of an increase in the number of microdefects in the material and a decrease in its brittle-fracture resistance. 1 2 3
School of Computer Science, Yangtze University, Jinzhou, China.
Karpenko Physicomechanical Institute, Ukrainian National Academy of Sciences, Lviv, Ukraine. Corresponding author; e-mail: [email protected].
Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 56, No. 1, pp. 68–75, January–February, 2020. Original article submitted June 11, 2019. 66
1068-820X/20/5601–0066
© 2020
Springer Science+Business Media, LLC
MATHEMATICAL MODELING OF THE INFLUENCE OF HYDROGEN ON THE CORROSION ACTIVITY OF METAL STRUCTURES
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Fig. 1. Schematic diagram of the rectilinear section of a heat-exchange pipe of steam generator with corrosion defect [18]. Numerous exam
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