Structural Levels of the Nucleation and Growth of Fatigue Crack in 17mn1si Steel Pipeline After Long-Term Service

The effect of sulfate-reducing bacteria (SRB) on the corrosion of steel 20 was investigated. Results demonstrated that the chemical composition of corrosion products, the corrosion rate, and corrosion type were altered due to the adherence of SRB and the subsequent formation of biofilm on the steel 20 surface. The micromechanisms of biocorrosion damage of specimens from pipe steel 20 were quantified on the basis of the microgeometry of the degraded surface and the localization parameters of corrosive stress microconcentrators. Stress concentrators in the vicinity of the micro-cuts, which are the depths of the profilograms, make it possible to evaluate safe (allowable) microcorrosion damage. The proposed approach complements the well-known methods for monitoring biodeterioration of pipe steels. With its help, it was found that a decrease in the corrosion rate of specimens with the addition of an inhibitor does not always clearly indicate its effectiveness. The case where the introduction of an inhibitor led to the destruction of the SRB biofilm on the surface of specimens from steel 20, but caused the activation of local corrosion processes and the formation of a more developed microrelief, is considered. The hollows of such microrelief are potential places of origin of defects, which require additional control.

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“…This will increase the stress concentration and reduce the pipe resistance to fracture within the main gas pipeline [25].…”

Section: Discussionmentioning

confidence: 99%

Microdefects of Biocorroded Pipe Steel Surfaces and Safety Assessment of Localized Stress Concentrators

Maruschak

Dzyura

Prentkovskis

et al. 2020

Metals

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“…A significant disadvantage is its relatively high price. In addition, the helium atom is of a very small diameter, enabling the helium to diffuse easily through solids, which translates into its losses [23][24][25]. For the purpose of our measurements, HE-4.6 helium was used.…”

Section: Methodsmentioning

confidence: 99%

Experimental Verification of the Impact of a Technical Gas-Using Pneumatic Coupling on Torsional Oscillation

Grega¹,

Krajňák²,

Moravič³

2018

SJSUT.ST

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The field of reducing torsional vibration of mechanical systems has seen the emergence of new flexible coupling designs. Our attention is focused on flexible pneumatic couplings. The flexible member of this coupling design is a pneumatic bag. The typical basic feature of such couplings is that the pneumatic bag allows for a change in air pressure. In the course of developing pneumatic couplings, we have experimented with the use of technical gases other than air for filling pneumatic bags. The aim has been to verify the impact of pneumatic couplings filled with other technical gases on the magnitude of torsional vibration in the mechanical system. For verification itself, two different gases have been used: helium, whose density is lower than air density, and propane butane, whose density is higher than air density. Experimental verification was performed under laboratory conditions on a mechanical system where torsion vibration was produced by a piston compressor.

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“…In the European Union, some of the trunks were laid underground. The total length of the gas pipelines in the Soviet Union in 1970 was 70 thousand kilometres, while in 1986, it reached 174 thousand kilometres [1,2]. Most of the pipes used for the trunks in the Soviet Union were the first-generation pipes made of normalised steel 17G1S GOST 19281-73 (1970s) [3].…”

Section: Introductionmentioning

confidence: 99%

“…The Minsk-Vilnius-Kaunas-Kaliningrad (Belorussia-Lithuania-Russia) gas pipeline (ø 530 mm), which is currently operating on the territory of the Republic of Lithuania, was put into operation in 1985. These pipelines have been operated for more than 30 years [1]. This period of pipeline operation was marked by the increased likelihood of accidents due to metal aging, fatigue, and corrosion.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Failure Pressure for Gas Pipelines with Combined Defects

Vilkys¹,

Rudzinskas

Prentkovskis

et al. 2018

Metals

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The paper presents the study of the influence of mechanical damage on the safe operation of gas transmission pipelines. The main types of pipeline damage with the actual parameters and their influence on the operational parameters are analysed. The damaged fractures of the section of the pipeline Kaunas (Lithuania)-Kaliningrad (Russia) were investigated in the laboratory. The main operational characteristics and the structure of the pipeline's metal after the period of long-term operation were determined using various research and experimental methods. The influence of the pipeline's damage was modelled by using the Finite Element Method and the ANSYS code. The predictions of the failure pressure were made, taking into consideration the actual properties of the pipeline's metal. Techniques including the hardness and microhardness measurement, chemical analysis, the impact strength test, and metallography analysis with an optical microscope, were used in the experimental study.

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Structural Levels of the Nucleation and Growth of Fatigue Crack in 17mn1si Steel Pipeline After Long-Term Service

Cited by 11 publications

References 20 publications

Microdefects of Biocorroded Pipe Steel Surfaces and Safety Assessment of Localized Stress Concentrators

Microdefects of Biocorroded Pipe Steel Surfaces and Safety Assessment of Localized Stress Concentrators

Experimental Verification of the Impact of a Technical Gas-Using Pneumatic Coupling on Torsional Oscillation

Evaluation of Failure Pressure for Gas Pipelines with Combined Defects

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