Taras Pyrig

Bio: Taras Pyrig is an academic researcher from Ivano-Frankivsk National Technical University of Oil and Gas. The author has contributed to research in topics: Deformation (engineering) & Welding. The author has an hindex of 3, co-authored 4 publications receiving 57 citations.

Fatigue and brittle fracture of carbon steel of gas and oil pipelines

Abstract: The areas of low frequency and corrosion fatigue for basic metal and welding joints of oil and gas pipelines have been determined on the basis of corrosion-fatigue test results. The most dangerous diapasons of the operation loadings were also determined. The present work also proposes the methodical approaches to the survivability prediction.

Structural and mechanical defects of materials of offshore and onshore main gas pipelines after long-term operation

Abstract: Abstract The study has established the main regularities of a fatigue failure of offshore gas steel pipes installed using S-lay and J-lay methods.We have numerically analyzed the influence of preliminary deformation on the fatigue life of 09Mn2Si steel at different amplitudes of cyclic loading. The results have revealed the regularities of formation and development of a fatigue crack in 17Mn1Si steel after 40 years of underground operation. The quantitative analysis describes the regularities of occurrence and growth of fatigue cracks in the presence of a stress concentration.

Influence of Preliminary Deformation on Micromechanisms of Failure of Offshore Gas Pipeline Material

Abstract: The S and J - methods of pipe laying tend to increase the brittle fracture component in the material, however, they have practically no effect on the residual life-time of metal under low amplitude cyclic loading (260 MPa). An increase in the stress range up to 320 MPa enhances the negative effect of preloading, which is more pronounced in case of using the S - method of pipe laying as compared to the J - one. Within the high amplitude range (420 MPa) the process of preliminary deformation causes the activation of relaxation processes and longitudinal splitting in the material, giving rise to an abnormal increase in the cyclic life of the plastically deformed material.

Degradation of the main gas pipeline material and mechanisms of its fracture

Abstract: The effect of the in-service scattered damage in the pipe wall metal is evaluated, and the effect of hydrogen absorbed by metal on the variation of the structure and mechanical properties of the main gas pipeline after a long-term operation is found. The main regularities in the graded nature of the static deformation process and the effect of hydrogenation on the scattered damage and fracture accumulation are found.

Evaluation of Failure Pressure for Gas Pipelines with Combined Defects

Abstract: 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.

Effect of Long Term Operation on Degradation of Material of Main Gas Pipelines

Abstract: The mechanisms of metal damage in the pipe of the main pipeline are investigated, the main reasons for their appearance are found and analysed. The main results are obtained by joint use of metallography, indentation, method for processing and analysis of digital images.

Defectiveness of external and internal surfaces of the main oil and gas pipelines after long-term operation

Abstract: Damage by pitting corrosion of the surface areas of the local oil and gas pipelines was identified and numerically analysed in this paper. Having used the methods of optical and scanning electron microscopy, the basic laws of structural and mechanical degradation were established. Based on the data of fractographic control, the shape of defects and substantiated morphological characteristics were examined. It was established that certain informative signs of the defects correspond to certain stages of operation. Having used methods of fractodiagnostics, the main reasons for the performance defects of main oil and gas pipelines were established, and the mechanisms of degradation as well as fracture of the materials they are made from were described. According to the findings, the cause of the decrease in the reliability of the main oil and gas pipeline networks is general and localised corrosion as well as technological defects in the pipeline metal. These studies are essential for the establishmen...