Stress-Corrosion Wear of Nitrided Steels in Acid Media

Stechyshyn, M. S.; Skyba, M. Ye.; Stechyshyna, N. M.; Martynyuk, А. V.

doi:10.1007/s11003-022-00660-4

Cited by 4 publications

(2 citation statements)

References 14 publications

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“…A power supply unit from an independent source, as well as a switching and control unit for a cyclically switched discharge, have been added to the scheme. In addition, the installation is additionally equipped with heating elements placed in the gas discharge chamber, which made it possible to arbitrarily change the energy parameters -the voltage U, and the value of the current density ϳ (the ratio of the current to the total area of the cage and suspension) [6].…”

Section: Methods Of Conducting Experimental Researchmentioning

confidence: 99%

Wear resistance of structural steels nitrided in a cyclically switched discharge with dry friction

Stechyshyn

Skyba

Martynyuk

et al. 2023

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The paper examines the method of conducting tribological studies in the dry mode of friction of nitrided and unhardened structural steels 20 and 45 in order to achieve comparable results of laboratory tests with operational characteristics. Preliminary studies of anodized steels of the same steels indicate that under conditions of extreme friction it is extremely difficult, and in some cases impossible, to use such values of specific pressure on the friction surface, at which it would be realistic to compare the results obtained for different samples made of different brands materials and processed using various technological processes. Since during the tests, constant lubrication of the friction zone was ensured, a layer of lubricant was present on the friction surface up to a certain pressure value, which led to extremely small indicators of linear wear. However, depending on the characteristics of the modified surface, there was a critical value of pressure at which the layer of lubricant was squeezed out of the friction zone, which led to instant adhesion of the surfaces. Thus, the study of wear resistance in the dry mode of friction ensures a significantly higher productivity of experiments. Unlike experiments with limit friction, dry friction can be used for different steels at the same pressure value, which eliminates the problem of comparability of results and contributes to the objectivity of conclusions regarding the effectiveness of various modification processes. According to the results of previous experiments, such a compromise pressure value can be 16 MPa. Another important phenomenon for the analysis of the influence of the modification results on the wear resistance characteristics of the surface is established - the effect of relaxation processes in the near-surface layers, which have already acquired structural transformations under the influence of pressure in the friction zone. For all steels, there is some slowing down of the intensity of wear after a break with a gradual return to the intensity characteristic of a certain brand of steel. The reason for such a phenomenon can only be the relaxation of stresses and the equalization of the characteristics of the structure in the near-surface layers. At the same time, the result is the strengthening of the surface, which explains the decrease in the intensity of the wear process. over time, as the strengthened layer breaks down, the indicators of the surface condition become equal to those before the break and the intensity of wear is restored.

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Section: Methods Of Conducting Experimental Researchmentioning

confidence: 99%

Wear resistance of structural steels nitrided in a cyclically switched discharge with dry friction

Stechyshyn

Skyba

Martynyuk

et al. 2023

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“…However, in different well-fluid environments, there may be different relationships between the corrosion behavior of different material surfaces and their stress corrosion susceptibility. Some researchers studied the stress corrosion resistance of high-strength steel, aluminum alloys, and magnesium alloys, measuring the stress corrosion resistance characteristics of specific materials in specific environments [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. However, in these studies, the material stress was constant, and the stress and corrosion environments were greatly different from the working environment of a high-strength sucker rod.…”

Section: Introductionmentioning

confidence: 99%

Study on Variable Stress Corrosion Susceptibility of Four Typical High-Strength Sucker Rods in High-Salinity Well Fluids

Zhang,

Li,

Zhu

et al. 2023

Processes

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To study the corrosion characteristics of high-strength sucker rods in high-salinity well fluids under alternating stresses, a single-factor stress corrosion test was designed. The slow strain rate tensile test (SSRT) was carried out for four kinds of high-strength sucker rods under different Cl− and HCO3− concentrations and with different service strengths, and the variable stress corrosion cracking susceptibility was analyzed. The results show that the elongation loss and absorbed work loss of the H-grade ultra-high-strength 4330 sucker rod after stress corrosion are greater than those of both the high-strength 4142 sucker rod and the high-strength 20CrMoA sucker rod. The elongation and absorbed work loss of the 30CrMoA and 20CrMoA sucker rods are less affected by the changes in Cl− and HCO3−. With the increase in use strength, the elongation and absorbed work loss of the high-strength sucker rod increase. The change in the surface of the sucker rod during the corrosion process is inconsistent with the actual elongation of the sucker rod and the absorbed work loss. It can be concluded that the stress corrosion cracking susceptibility of the sucker rod is not necessarily related to the tensile strength of the sucker rod. The 4330 sucker rod is not suitable for applications in wells with a high concentration of Cl−, but it is suitable for operation in alkaline conditions where corrosive media such as HCO3− and Cl− coexist. Under highly corrosive and highly mineralized conditions, the 30CrMoA sucker rod is less susceptible to stress corrosion. The stress corrosion cracking susceptibility of the 20CrMoA sucker rod is lower than that of the 4142 sucker rod. In high-salinity well fluids, the higher the use strength, the higher the stress corrosion cracking susceptibility of the high-strength sucker rod is. The test results for the weight-loss-based corrosion rate and plastic loss may contradict the determination of the corrosion susceptibility of the material under working conditions.

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