Wyniki wyszukiwania - BazTech

1

Corrosion of pipe steels 20 and 17G1S-U in ground electrolytes with a hydrogen indicator close to neutral

Polutrenko M., Maruschak P., Babii A., Prentkovskis O.

Archives of Materials Science and Engineering

|

2021

|

Vol. 108, nr 1

16--23

EN

Purpose: of this paper is to analyse the mechanism of near-neutral pH corrosion of main gas pipelines. The stages of main gas pipelines in model environments that meet the soil conditions of Ukraine have been studied. Design/methodology/approach: The corrosion rate of steel specimens from steels 17G1S-U and 20 and the influence of borate buffers on their protective properties were evaluated. The influence of corrosion time on changes in pH of model media is shown. Morphological features of surface damages of pipe steels are established. The defect analysis of specimens from steels 17G1S-U and 20 by electron scanning microscopy is carried out. Findings: The effect of borate buffers on the protective properties of the steel grades studied was revealed, and changes in the pH of the model media during corrosion processes were described. The main regularities in corrosion, as well as the surface morphology of damaged specimens, were studied by scanning electron microscopy. Research limitations/implications: Detailed investigation of localised corrosion phenomena induced by inclusions that are present in steels 17G1S-U and 20 is extremely critical. In particular, there is still ambiguity as to whether the localised corrosion initiation induced by non-metallic inclusions is an electrochemical process or a chemical process. Practical implications: The research findings will be used when testing specimens from pipe steels under cyclic loading in the model media studied, as well as for predicting the residual life of gas pipelines with corrosion defects. Their generalization will make it possible to develop the effective methods of ground diagnostics and prediction of SCC of main pipelines. Originality/value: It was found that the corrosion rate is determined by internal (nature and properties of the metal) and external (properties of the aggressive medium and the corrosion process conditions) factors. The protective effect for steel 17G1S in medium NS4 + borate buffer (1: 1) was 61.5%. Steel 20 had the greatest protective effect in medium NS4 + borate buffer (1: 3), which was 87.05%.

2

Fatigue and failure of steel of offshore gas pipeline after the laying operation

Poberezhnyi L., Maruschak P., Prentkovskis O., Danyliuk I., Pyrig T., Brezinová J.

Archives of Civil and Mechanical Engineering

|

2016

|

Vol. 16, no. 3

524--536

EN

The presented paper is mainly aimed at estimating the residual lifetime of metal used for the offshore gas pipeline under a low amplitude cyclic load applying S- and J-methods for pipelaying. Taking into account the preliminary effect of deformation on the welded joint and the base material of the pipe, the tests on fatigue have been carried out and physical and mechanical regularities in fatigue failure in offshore gas pipeline materials have been established. The obtained results show that the plasticity and embrittlement of the pipe wall employing S- and J-methods for pipelaying do not practically affect the residual lifetime of metal under low amplitude cyclic loading, but rather exert a significant influence within a high amplitude range under the preliminary deformation process that activates the accumulation of fatigue defects and strain aging.

3

Simulation of the system “ road - vehicle - obstacle ”

Prentkovskis O., Bogdevicius M., Lingaitis L.P. L.P.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

|

2001

|

z. 17

169-176

EN

The general mathematical model of the system “ road - vehicle - obstacle ”, which consists of the models of road pavement surface, vehicle, rigid and deforming obstacles, and the interaction between the vehicle and the obstacle has been constructed. The variation of interaction force and contact position are estimated at the moment of the vehicle collision with the obstacle. The model evaluates interaction of the vehicle wheels with the road pavement surface; blocking of wheels; change of forces (air resistance, cohesion and centrifugal), which influence the vehicle. According to the generał mathematical model of the system “ road - vehicle - obstacle ”, different traffic situations can be investigated on certain road sections with known physical and mechanical properties of the road surface.

PL

Został utworzony model matematyczny systemu “droga -samochód (inny środek transportu) - przeszkoda“, składający się z modeli: odcinka drogi; samochodu; deformującej i nie deformującej się przeszkody; wzajemnego oddziaływania samochodu i przeszkody. Podczas wzajemnego oddziaływania samochodu i przeszkody (np. ogrodzenia drogi) bierze się pod uwagę: zmianę sił oddziaływania; zmianę miejsca kontaktu samochodu z przeszkodą; fizyko-matematyczne parametry powierzchni drogi; istnienie kontaktu między kołami samochodu a powierzchnią drogi; blokowanie kół samochodu; zmianę sił (siły oporu powietrza; siły kontaktu kół samochodu z powierzchnią drogi; siły odśrodkowej), działających na samochód. Za pomocą ogólnego matematycznego modelu systemu “droga - samochód (inny środek transportu) - przeszkoda“ można modelować i badać różne sytuacje ruchu transportowego na konkretnym odcinku drogi.