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EN
According to the official report contained in the document „Demographic forecasts for the years 2003-2030,” we are witnessing a demographic disaster whose effects will feel in a few years. Demographic research and analysis indicate that lasted for several years, fertility decline has not ended and concerns are increasingly successive generations of young people. It will continue to a decline in mortality and a systematic increase in the average life expectancy to around 77.6 years for men and 80 years for women in 2030. Demographic forecasts Central Statistical Office show that the number of people of retirement age will increase to 9.6 million in 2030 (GUS 2004). With the increase in the proportion of people over 60 years of age in Polish society there is a need to create special programs to guarantee access to specialized health services that promote „the successful aging” and such, so that their lives will be socially and economically useful. For the elderly, which due to their age is often accompanied by various kinds of disability it is offered the most available form of rehabilitation namely turnus rehabilitation and streamlining. The main objective of the study was to analyze the impact rehabilitation program offered during the two-week camps rehabilitation and to improve the individual parameters of the functional capacity of the participants. The study sample consisted of 509 aged 55 to 87 years .The primary objective was to answer the question whether the rehabilitation program improves coordination complex, agility and balance in seniors. The study shows that the rehabilitation program significantly improves complex coordination, agility and balance in seniors, which is very significant and positive effect on reducing the risk of falls. The team of men better result was observed in 75% of all respondents and nearly 90% of the team of women .. In addition, studies have shown that Fullerton Fitness Test can be recommended as a tool to assess the progress evaluation of improvement when they take seniors various forms of physical activity.
EN
The paper presents results of research on the influence of cooling rate on the structure and properties of G17CrMoV5 - 10 (L17HMF) cast steel. The material for research was a section taken out from an outer cylinder of a steam turbine body after about 250 000 hours of operation at the temperature of 535oC and pressure 9 MPa. The investigated cast steel was subjected to heat treatment which consisted in cooling at the rates corresponding to the processes, such as: bainitic hardening, normalizing and full annealing. Tempering after the process of cooling from austenitizing temperature was carried out at the temperatures of: 700, 720 and 740oC. Performed research has proved that structures obtained after bainitic hardening and normalizing are characterized by a large strength margin which allows to apply high temperatures of tempering. It has been shown that the cast steel of bainitic structure, with similar mechanical properties as the cast steel of bainitic - ferritic structure, is characterized by almost twice as high impact energy. Full annealing and tempering of the examined cast steel ensures only the required impact strength, with mechanical properties comparable to those after service.
PL
W pracy przedstawiono wyniki badań wpływu regenerującej obróbki cieplnej na strukturę i własności długotrwale eksploatowanego staliwa L21HMF. Wykazano, że struktura odpuszczonego bainitu zapewnia uzyskanie w staliwie o strukturze zdegradowanej długotrwałą eksploatacją w podwyższonych temperaturach, wysokich własności wytrzymałościowych i udarności KV > 100J. Uzyskane własności mechaniczne w zregenerowanym staliwie przewyższają wymagania stawiane nowym odlewom.
EN
This paper presents the results of investigation of influence of regenerative heat treatment on the structure and properties of long - term serviced L21HMF cast steel (symbol according to Polish Standard. It has been shown that the structure of tempered bainite ensures high mechanical properties and impact energy KV > 100J, in the cast steel which, degenerated structure caused by long - time operation at elevated temperatures. Obtained mechanical properties in regenerated cast steel exceed the requirements for new castings
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Content available remote Heat treatment of long term serviced Cr - Mo cast steel
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EN
The paper presents results of research on the influence of heat treatment on the structure and properties of L20HM cast steel after long term operation at elevated temperature. Investigated cast steel was taken out from an outer frame of a steam turbine serviced for 167 424 hours at the temp. of 535 °C and pressure 12.75 MPa. In post-operating condition the investigated cast steel was characterized by mechanical properties below the required minimum and by high brittleness. Performed research on the influence of austenitizing parameters has revealed that the range of austenitizing temperatures for the examined cast steel: A_c3 +30 ÷ 60 °C ensures obtaining of a fine austenite grain, homogeneous in size. It has been proved that tempering of bainititc - ferritic structure above 680 ÷ 690 °C causes an increase of impact energy along with a decrease of mechanical properties below the required minimum. Moreover, it has been noticed that applying of under-annealing instead of tempering, after full-annealing, guarantees the required impact energy of KV > 27J, with the mechanical properties similar to those after service.
PL
W artykule przedstawiono charakterystykę niejednorodnych doczołowych złączy spawanych rur VM12/13CrMo4-5 i P91/10CrMo9-10 łączonych spoiwem EPRI P87. Badaniu poddano złącza wykonane bez podgrzewania wstępnego i bez obróbki cieplnej po spawaniu. Zakres przeprowadzonych badań obejmował badania mikrostrukturalne przy użyciu mikroskopii świetlnej oraz badania właściwości mechanicznych – pomiar twardości złączy oraz statyczną próbę rozciągania.
EN
The article presents the characteristics of heterogeneous butt welded joints of pipes VM12/13CrMo4-5 and P91/10CrMo9-10 welded with filler metal EPRI P87. The study was performed on weld joints made without preheating and without heat treatment after welding. The scope of the research included the microstructural studies using light microscopy and the study of mechanical properties - measurement of weld joints hardness, and static tensile test.
PL
W pracy przedstawiono opracowane przez autorów wykresy CTP dla staliwa gatunków G17CrMo5-5 i G17OMoV5-10, pomocne przy ustalaniu zakresu szybkości chłodzenia odlewów z temperatury austenityzowania, aby uzyskać optymalną strukturę bainityczną. Wykazano, ze struktura odpuszczonego bainitu, charakteryzująca się dużymi wartościami właściwości wytrzymałościowych i bardzo dużą udarnością KV > 100 J, zapewnia uzyskiwanie udarności KV > 27 J także w staliwie o strukturze, zdegradowanej długotrwałą eksploatacją w podwyższonej temperaturze.
EN
The work presents the CTP diagrams developed by the authors for cast steel grades G17CrMo5-5 and G17CrMoV5-10, which are helpful when determining range of casting cooling rate from austenitizing temperature in order to obtain optimal bainitic structure It hes been proved that tempered bamite structure, which features high strength characteristic values and very large impact strength KV > 100 J, ensures that impact strength values KV > 27 J are obtained also in cast steel with structure degraded by prolonged operation in increased temperature.
EN
The paper presents an effect of stress relief annealing, applied to casts after the repair by welding, on the microstructure and mechanical properties of quenched and tempered martensitic GX12CrMoVNbN9 – 1 cast steel (called GP91). The test pieces being the subject of research were taken out from a test coupon. Heat treatment of GP91 cast steel was carried out at the parameters of temperature and time appropriate for the treatment of multi-ton steel casts, while stress relief annealing was performed at the temperatures of 730 and 750ºC. After quenching and tempering GP91 cast steel was characterized by the microstructure of high-tempered martensite with numerous precipitations of carbides of diverse size. Mechanical properties of the investigated cast steel after heat treatment fulfilled the standard requirements. Stress relief annealing contributes to the processes of recovery and recrystallization of the matrix as well as the privileged precipitation of M23C6 carbides on grain boundaries. Changes in the microstructure of the examined cast steel cause deterioration in mechanical properties – the higher the temperature of stress relief annealing, the greater the deterioration.
9
Content available remote Optimisation of regenerative heat treatment parameters of G21CrMoV4-6 cast steel
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EN
Purpose: of the paper was to design the optimal parameters of regenerative heat treatment of G21CrMoV4-6 (L21HMF) cast steel after long-term serviced at elevated temperature. Design/methodology/approach: The data obtained from dilatometric curves were used to determine the optimal cooling rates leading to acquire the bainite microstructure with the ferrite amount lower than 10%. Structures were investigated using light optical microscopy and scanning electron microscopy. In order to determine stability of carbide precipitates the equilibrium temperatures of precipitates dissolving were defined using thermodynamic databases of Thermo-Calc software. Findings: The tempered bainitic microstructure of the Cr-Mo-V cast steel has the very good mechanical properties and impact energy. The optimal bainite or bainite with a small amount of ferrite (<10%) structure can be obtained after cooling with the cooling rates 13.64 K/s ≥ v 8-5 ≤ 33. 33K/s. The optimal tempering temperature range of the bainitic G21CrMoV4–6 cast steel equals 710-720 °C and ensures high mechanical properties and impact energy. Practical implications: The above mentioned heat treatment is the new type of regenerative heat treatment of elements long term serviced at elevated temperatures. Heat treatment leads to the obtaiment of very good mechanical properties and high impact energy. Originality/value: The paper shows the possibilities of regenerative heat treatment long term serviced cast steels for lifetime extension.
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PL
Badaniu poddano złącza spawane staliwa GX5CrNi13-4. Złącza zespawano wykorzystując różne techniki spawania metodą MMA (111) w pozycjach: PC i PF. Na uzyskanych złączach wykonano nieniszczące i niszczące badania ich jakości. Przeprowadzone badania wytrzymałości na rozciąganie oraz próby gięcia złączy spawanych wykazały, że niezależnie od pozycji i techniki spawania, otrzymane połączenia spełniają wymagania normy dla materiału rodzimego. Udarność złącza spawanego w pozycji PF niezależnie od temperatury badania spełniała zarówno wymagania przepisów DNV, jak i normy materiałowej. W przypadku pozycji PC badane złącze w spoinie spełniało wymagania minimalnej udarności w temperaturze obniżonej, natomiast w temperaturze otoczenianie. Twardość złącza spawanego po obróbce cieplnej niezależnie od pozycji spawania była niższa od wartości 350 HV. Rozkład twardości w złączu spawanym w pozycji PF charakteryzował się mniejszym gradientem twardości na przekroju w porównaniu do złącza spawanego w pozycji PC. Wykazano, że można uzyskać złącze o bardzo dobrych właściwościach wytrzymałościowych staliwa o ograniczonej spawalności, jeżeli zastosuje się właściwą technologię spawania.
EN
The investigation was carrier out on welded joints of GX5CrNi13-4 cast steel. The joints were welded using various welding techniques with the MMA method (111) in the positions: PC and PF. On the obtained joints, the non-destructive and destructive tests of their quality were performed. These tests have shown a correct structure of the joints, without any welding non-conformities. The tests of tension and bending carried out on the welded joints have shown that the obtained results fulfil the standard requirements for the base material, regardless of the position and technique of welding. Impact strength of the welded joint in position PF met both the requirements of DNV regulations, as well as material standard, irrespective of the temperature of testing. In the case of position PC, the welded joint in the weld seam fulfilled the requirements of minimum impact strength at decreased temperature, whereas at room temperature it did not. The distribution of hardness of the welded joint in the cross section after heat treatment, regardless of the welding position, was lower than the value of 350 HV. Hardness distribution in the welded joint in position PF was characterized by a smaller gradient of hardness in the cross section, compared with the welded joint in position PC. It has been proved that obtaining a joint of very good strength properties for the cast steel of limited weldability is possible if a proper welding technology is applied.
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Content available remote Heat treatment of cast steel using normalization and intercritical annealing
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EN
The paper presents the influence of heat treatment, normalization with subsequent ([alpha]+[gamma]) annealing on the structure and properties of G21CrMoV4-6 (L21HMF) cast steel, long term serviced at the temp. of 540 oC. Applying of heat treatment ensures obtaining of regenerated ferritic – pearlitic structure with pearlite precipitations mainly on grain boundaries. such a structure formed after slow cooling at two-phase range, ensures a significant impact energy growth with mechanical properties similar to the properties after service. It has also been proved that tempering at temperatures recommended by the norm does not always allow to obtain the required minimum impact energy.
PL
W pracy przedstawiono wyniki badań wpływu różnych szybkości chłodzenia na strukturę i własności staliwa L21HMF poddanego regenerującej obróbce cieplnej. Optymalny zakres szybkości chłodzenia, dla uzyskania struktury bainitycznej, wyznaczono w oparciu o wykonany wykres CTPc. Wykazano, że struktura odpuszczonego bainitu zapewnia w badanym staliwie optymalne skojarzenie własności wytrzymałościowych i udarności.
PL
W pracy przedstawiono wpływ regenerującej obróbki cieplnej w zakresie dwufazowym (...) na strukturę i własności niskostopowego staliwa Cr - Mo - V po długotrwałej eksploatacji w podwyższonej temperaturze. Wykazano, że wyżarzanie jednostopniowe w zakresie dwufazowym zapewnia uzyskanie drobnoziarnistej struktury ferrytyczno - perlitycznej o wymaganej udarności KV >27J. Umożliwia to zastosowanie po naprawach przez spawanie (w ramach rewitalizacji), jedynie wyżarzania w zakresie dwufazowym w celu uzyskania poprawy własności plastycznych złącza spawanego i eksploatowanego staliwa.
EN
This work deals with the influence of regenerative heat treatment during annealing in (...) temperature range on the structure and properties of low-alloy Cr - Mo - V cast steel after long-term operation. It has been shown that intercritical annealing ensures obtaining of fine-grained ferritic - perlitic structure which guarantees required impact energy KV >27J in regenerated cast steels. This enables application (after repairs through welding within the confines of revitalization) of (...) annealing in order to improve plastic properties of the weldment and utilized cast steel.
PL
Przedstawiono wyniki badań własnych wpływu niskocyklicznego zmęczenia w temperaturze pokojowej i 600'C na mikrostrukturę żarowytrzymałego, wysokochromowego staliwa GX12CrMoVNbN9 - 1 (GP91). Charakterystykę mikrostruktury badanego staliwa po zmęczeniu niskocyklowym przeprowadzono za pomocą transmisyjnej mikroskopii elektronowej i analizy mikrostruktury dyslokacyjnej i morfologii węglików. Wykazano, że zmęczenie w zakresie niskocyklowym staliwa GP91 prowadzi do procesu zdrowienia i poligonizacji osnowy w wyniku spadku gęstości dyslokacji i wzrostu szerokości podziaren, a w podwyższonej temperaturze(600'C) skutkuje dodatkowo procesem koagulacji węglików M23C6. Intensywność powyższych procesów zależy nie tylko od temperatury badania, ale również od poziomu amplitudy odkształcenia całkowitego εac, Wskazuje to na przewagę procesów mięknięcia mikrostruktury staliwa GP91 w wyniku zmęczenia niskocyklicznego nad procesami umocnienia, co wpływa na właściwości cykliczne badanego staliwa.
EN
The paper presents the results of an independent research on the influence of low-cycle fatigue at room temperature and 600'C on the microstructure of high-temperature creep resisting high-chromium GX12CrMoVNbN9 - 1 (GP91), cast steel. The characteristics of the microstructure of the examined cast steel after low-cycle fatigue was made by means of transmission electron microscopy and included an analysis of the dislocation microstructure and morphology of carbides. It has been shown that the low-cycle fatigue of GP91 cast steel leads to the processes of recovery and polygonization of the matrix, as a result of a decrease in the dislocation density and growth of subgrain width. Additionally, at an elevated temperature (600'C), it results in the process of coagulation of M23C6, carbides. Intensity of the above-mentioned processes depends not only on the temperature of testing, but also on the level of total strain amplitud εac This proves the advantage of softening processes in the GP91 cast steel microstructure, due to low-cycle fatigue, over the strengthening processes, which has an influence on the cyclic properties of the investigated cast steel.
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