OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Residual stresses of opposite sign can occur in the material during cold rolling due to inclusions [20]. The reverse stress can increase the anisotropy of the material. We can observe the results of such a process in fig. 6. Sources of anisotropy can be other microstructure features besides texture and grain morphology, such as oriented dislocation structures [21–23]. We use the influence coefficient to determine the influence of internal stresses on the corrosion rate. This coefficient is determined by determining the small deviations observed between the parameters under study. max i i i i Y Y X N X Y − = D , (2) where Xi is the corrosion rate value; Yi is the magnitude of internal residual stresses; ΔXi is the incremental value of corrosion rate; Yi is the maximum internal residual stresses. The influence coefficient of internal stresses is determined from the central region of the experimental dependence by formula 2. We find that the coefficient of influence of the magnitude of internal stresses on the corrosion rate is 0.72. Conclusion 1. It is established that the initial state of the material has a direct effect on the corrosion process in an aggressive medium. This effect is illustrated using the example of deformation of St3 structural steel and changes in its corrosion rate in a 5 % hydrochloric acid solution. 2. It is found that with increasing the degree of plastic deformation along the rolling direction, the magnitude of internal stresses increases. The magnitude of internal stresses is governed by a linear correlation dependence on the magnitude of residual strain of the material with a coefficient of determination R2 ≈ 0.98. 3. When the degree of plastic deformation increases, there is an ambiguous change in the value of grain anisotropy, which is associated with internal effects occurring in the structure of the material processes during plastic deformation, such as: the sliding of the crystal lattice in the directions {110} <111>; the occurrence of inverse residual internal stresses due to the presence of inclusions in the steel structure. 4. The magnitude of internal residual stresses and corrosion rate of the material have a direct linear relationship, which is described by a regression equation of linear type with R2 ≈ 0.92. Thus, the coefficient of influence of the magnitude of internal stresses on corrosion rate is equal to 0.72, that proves the presence of interrelation between the parameters under consideration. References 1. Zhuikov I.V., Gareev D.V., Popov G.G., Bolobov V.I. [Influence of the stressed-deformed state of the pipeline metal on the rate of formation of grooving corrosion]. Sovremennye obrazovatel’nye tekhnologii v podgotovke spetsialistov dlya mineral’no-syr’evogo kompleksa: III Vserossiiskaya konferentsiya [Proceedings 3rd All-Russian Conference “Modern educational technologies in training specialists for the mineral resource complex”]. St. Petersburg, 2020, рр. 1364–1370. (In Russian). 2. Zainyllin R.S., Zainyllina A.R. Vzaimosvyaz’ skorosti korrozii i napryazhenno-deformirovannogo sostoyaniya stali [Relationship of corrosion rate and tensions strain state of steel]. Neftegazovye tekhnologii i novye materialy. Problemy i resheniya [Proceedings of scientific papers “Oil and Gas Technologies and New Materials. Problems and solutions”]. Ufa, 2016, iss. 5 (10), рр. 347–353. 3. Gorelik S.S., Rastorguev L.N., Skakov Yu.A. Rentgenograficheskii i elektronnoopticheskii analiz [X-ray and electron optical analysis]. Moscow, Metallurgiya Publ., 1970. 366 p. 4. Zernii Yu.V. Osnovy tochnosti i upravleniya kachestvom v priborostroenii [Fundamentals of accuracy and quality management in instrumentation]. Moscow, Moscow State Academy of Instrument Engineering and Computer Science Publ., 2003. 170 p. 5. Novikov I.I. Defekty kristallicheskogo stroeniya metallov [Defects in the crystal structure of metals]. Moscow, Metallurgiya Publ., 1975. 208 p.
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