Wyniki wyszukiwania - BazTech

1

Właściwości eksploatacyjne stali niskostopowej po obróbce tarciowo-mechanicznej w środowisku sztucznej wody morskiej

Kocańda D., Nykyforchyn H., Torzewski J., Jurczak W., Świątek K.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2011

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z. 99

107-109

EN

The paper presents the results of the research into improving exploitative and fatigue properties of S235JR and S355J2 low alloyed steels by means of FSP process in an artificial sea water. Extensive program of the study elaborated for this goal has proved that the FSP technique can lead to better mechanical and exploita- tive properties of the examined steels.

2

Correlation between degradation of corrosion and mechanical properties of long-term exploited oil and gas pipeline steels

Nykyforchyn H., Tsyrulnyk O., Hredil M., Zvirko O.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2011

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z. 99

41-43

EN

Main oil and gas pipelines are designed for long-term service, exceeding 30 years therefore the degradation processes taking place in the materials should be considered. The aim of the paper is to present results obtained in the investigations of the in-bulk degradation pipelines and oil storage tank steels. The mechanical and electrochemical properties were tested.

3

Problems of hydrogen interaction with metals and methods of structures lifetime estimation.

Kurzydłowski K., Nykyforchyn H.

Prace Naukowe Instytutu Materiałoznawstwa i Mechaniki Technicznej Politechniki Wrocławskiej. Konferencje

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2007

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Vol. 65, nr 11

55-69

EN

The hydrogen induced degradation of the properties and microstructure of the low carbon low-alloyed steels due to exploitation and exposition to the hydrogenated environment at ambient and elevated temperatures have been considered. The essential decrease of mechanical (impact strength, creep), corrosion (corrosion rate) and corrosion-mechanical (stress corrosion cracking) properties of exploited metal to compare with that in the virgin state is demonstrated. Especially high sensitivity of an effective range of stress intensity factor of fatigue crack growth to in-service degradation is shown. Weld metal is more sensitive to hydrogen degradation and even tensile mechanical properties of strength and plasticity are sensitive enough to "in-bulk" material degradation. An approach to the residual life time evaluation of the power plant steam pipe lines is developed, which allows to take into account the negative hydrogen effect. Some electrochemical parameters are especially sensitive to in-service degradation of steels at high and low temperatures as well. A good correlation between changes of electrochemical and mechanical properties in the steel degradation process gives prospects for the development of NDT methods for evaluation of the current state of exploited steels. The results discussed show that inspection of the surfaces of installations to find corrosion or mechanical damage alone may not be sufficient for proper evaluating risk of failure.

4

Stress corrosion cracking of the clad structural steel after its high temperature hydrogen degradation

Lubińska K., Tsyrulnyk O., Herdil M., Nykyforchyn H., Kurzydłowski K. J.

Advances in Materials Science

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2007

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Vol. 7, nr 1(11)

27-32

EN

It is known that long term service of installations in energy and refinery industry in conditions of simultaneous action of loading and corrosion-hydrogen environments causes degradation of structural steels. This process of degradation is the most intensive on grain boundaries. Therefore structures with clad metal, namely, refinery shell, should be especially sensitive to degradation process. Three types of clad metal "low alloy steel/stainless steel" were studied: 15HM/304L, 516GR60/410S and 5l6GR70/N201. In-service degradation was modeled by thermocycling of specimens in the range of 25-550 st.C in hy-drogen atmosphere with fast rate of cooling. It allows to fix at law temperature such amount hydrogen in metal which is in equilibrium at high temperature and this is the reason of the intensive hydrogen degradation. Metal was tested after 30 and 100 thermocycles. Sensitiveness to hydrogen degradation was evaluated by slow strain rate tension of specimens during moderate cathodic polarisation. Same peculiarities of hydrogen cracking of clad metal were established and it was revealed that thermocycling in hydrogen atmosphere increases sensitivity of clad metals to hydrogen degradation. The degradation level depends on the type of clad metal and number of thermocycling.

5

Peculiarities of hydrogen effect on the creep process in the Cr-Ni-Mo steel

Zagórski A., Student O., Babij L., Nykyforchyn H., Kurzydłowski K.J.

Advances in Materials Science

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2007

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Vol. 7, nr 1(11)

211-218

EN

Stability of the metal mechanical properties of oil hydrocracking reactor shell during long term exploitation is very important for guarantee of safe service. It is significant to investigate a metal after different duration of its service for prediction of work ability of material. The simultaneous effect of high temperature and hydrogen on an intensity of metal degradation is revealed. Besides, by comparison of creep strain Tales in air and hydrogen, is shown effect of hydrogenation on steady stale creep of metal in virgin stale and after service. In particular creep strain rate in virgin and degraded in service conditions steels is higher in hydrogen than in air. The mechanism of hydrogen effect is revealed. It is shown that tests in hydrogen make systems of sliding made active and it provides localization of creep process in the narrow strip and fracture macroorientation in direction of the tangent stresses action.

6

Corrosion-Hydrogen Degradation of the Oil Transportation Pipeline and Storage Tank Steels Exposed to a Long Time Service Conditions

Nykyforchyn H., Kurzydłowski K.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2005

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z. 79

205-222

7

Effect of hydrogen degradation of structural steels on the fatigue crack growth

Nykyforchyn H.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2001

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z. 67

203-218

EN

A number of effects of hydrogen both as gas and dissolved in metal on the fatigue crack growth in steels, especially at the near threshold load, has been analysed: 1) the effect of gas adsorption on the effective fatigue threshold [delta]Kth eff; 2) analysis of hydrogen effect on the fatigue crack growth in structural steels in dependence of its strength and test temperature; 3) application of fracture mechanics approaches to the evaluation of high temperature hydrogen degradation of steels; 4) use of the [delta]Kth eff parameter for evaluation of the high temperature degradation of steels during operation in hydrogen-containing environment; 5) existence of three factors of ambiguous hydrogen influence on [delta]Kth eff; 7) fractografical peculiarities of the near threshold crack growth in the degraded steel; 9) a geometric model of crack closure in the hydrogenated steel caused by fracture surface roughness and the longitudinal shear; 10) scale effect of the fatigue threshold; variance of [delta]Kth under the plane strain conditions; dependence of [delta]Kth on the specimen thickness for the hydrogenated and degraded metal.

8

Hydrogen effect on fatigue threshold of structural steels.

Nykyforchyn H., Student O., Łunarska E.

Inżynieria Materiałowa

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2001

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R. XXII, nr 5

672-675

EN

A number of effects of hydrogen both as gas and dissolved in metal on the threshold fatigue crack growth in steels has been analysed: the effect of gas adsorption on the effective fatigue threshold delta Kth ef int; fatigue crack growth in structural steels in dependence of its strength and test temperature; use of the delta Kth ef int parameter for evaluation of the high temperature degradation of steels during operation; existence of three factors of ambiguous hydrogen influence on delta Kth ef int; a geometric model of crack closure in the hydrogenated steel caused by fracture surface roughness and the longitudinal shear; scale effect of the fatigue threshold.

PL

Zrobiono analizę całego szeregu fenomenów wpływu wodoru jako bazowego środowiska, tak i rozpuszczonego w metalu, na przyprogowy wzrost zmęczeniowych szczelin w stali; adsorbcyjny wpływ gazu na efektywny próg zmęczenia delta Kth ef int; zmęczeniowy wzrost szczelin w konstrukcyjnych stalach w zależności od ich mocności i temperatury badań; wykorzystanie parametru delta Kth ef int dla oceny wysokotemperaturowej degradacji stali; istnienie trzech czynników niejednoznacznego wpływu wodoru na delta Kth ef int; geometryczny model zamknięcia szczeliny w wodorowanej stali spowodowany szorstkością powierzchni i wzdłużnym zasuwem; skalowy efekt progu zmęczenia.

9

Eksperymentalna metoda badania zmęczeniowego wzrostu szczeliny z wykorzystaniem opisu energetycznego.

Szata M., Nykyforchyn H.

Prace Naukowe Instytutu Materiałoznawstwa i Mechaniki Technicznej Politechniki Wrocławskiej. Konferencje

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1999

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Vol. 61, nr 9

67-72

PL

Przedstawia się metodykę budowy kinetycznych wykresów pękania zmęczeniowego z wykorzystaniem opisu energetycznego. Metoda polega na doświadczalnym wyznaczaniu wyznaczaniu pętli histerezy energii dla pełnego dla pełnego cyklu obciążenie - odciążenie próbki przy uwzględnieniu analizy teoretycznej procesu. Odkształcenie próbki mierzone jest po obu stronach koncentratora ze szczeliną z wykorzystaniem specjalistycznego oprzyrządowania ze szczeliną z wykorzystaniem specjalistycznego oprzyrządowania. Układ pozwala zwiększyć dokładność rejestracji składowej plastycznej odkształcenia. Proponowane metoda rejestracji pętli histerezy charakteryzuje się wystarczającą dokładnością dla prędkości wzrostu szczeliny powyżej 10-7m/cykl. Metodę sprawdzano na stali 12HMF używanej w energetyce. Otrzymano kinetyczny wykres zmęczeniowego pękania tej stali, który jest niewrażliwy na zmiany asymetrii cyklu obciążenia.

EN

Method of building of the fatigue kinetic diagrams is created using the energy approach. It based on the experimental determination of the energy hysteresis loops of the full loading-unloading cycle, and the certain theoretical pre-conditions. The special device was used for registration of deformation, which surrounds concentrator with crack from the both sides. It eliminates the elastic component of deformation and increase the sensitivity of the plastic component record. Proposed method of the hysteresis loop registration shows the sufficient sensitivity at crack growth velocities above 10-7 m/cycle. Method was tested on the 12HMF steel of the power energy steam pipe-lines. The united fatigue fracture kinetic diagram of steel is obtained for the different levels of assymetry with using of this approach.