Wyniki wyszukiwania - BazTech

1

Wybrane własności eksploatacyjne silników asynchronicznych klatkowych zasilanych napięciem o dużej częstotliwości

Zielińska M. J.

Maszyny Elektryczne : zeszyty problemowe

|

2013

|

Nr 1(98)

149-152

PL

Indukcyjne silniki klatkowe zasilane napięciem o dużej częstotliwości stosowane są głównie w przemyśle łożyskowym, precyzyjnym i włókienniczym. Są więc mało znaną grupą maszyn. Skromna jest również literatura dotycząca tego typu silników. Największe częstotliwości, czyli najwyższe prędkości obrotowe wynikają z potrzeb technologicznych i ograniczone są możliwościami wykonawczymi. Silniki te posiadają swoją specyficzną konstrukcję i mają określone własności eksploatacyjne różniące je od maszyn indukcyjnych klatkowych zasilanych napięciem o częstotliwości 50 Hz. Różnice te wynikają głównie z wprowadzenia intensywnego chłodzenia dla zmniejszenia wymiarów gabarytowych, zastosowania żłobka zamkniętego w wirniku celem ograniczenia drgań i hałasu oraz zasilania silnika napięciem o dużej częstotliwości. W niniejszym artykule na podstawie rozważań teoretycznych i badań laboratoryjnych podjęto próbę określenia własności silników asynchronicznych klatkowych zasilanych napięciem o dużej częstotliwości. Rozważania dotyczą parametrów elektromagnetycznych, bilansu strat jak również doboru wartości napięcia zasilania celem zapewnienia zadanych parametrów eksploatacyjnych.

EN

Induction squirrel-cage motors powered by high-frequency voltage are mainly used in industrial bearing, precise and textile industries. They are so little known group of machines. Literature concerning engines of this type is also modest. The highest frequency, which is the highest speeds on the needs of technological and regulatory capabilities are limited. These motors have their specific design and have specific operational properties differ them from cage induction machines supplied voltage with a frequency of 50 Hz. These differences result mainly from implementing the intensive cooling for reducing dimensions, of applying the groove closed in the rotor in order to limit pulses and the noise and contributing towards the engine stretching about the great frequency. In the present article based on theoretical deliberations and laboratory tests an attempt to determine the ownership of squirrel-cage asynchronous motors was made fed with stretching about the great frequency. Deliberations concern electromagnetic parameters, balance of losses as well as the selection of the value of the supply voltage in order to ensure set exploitation parameters.

2

PVD and CVD gradient coatings on sintered carbides and sialon tool ceramics

Dobrzański L. A., Staszuk M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2010

|

Vol. 43, nr 2

552--576

EN

Purpose: The main objective of the work is to investigate the structure and properties of multilayer gradient coatings produced in PVD and CVD processes on sintered carbides and on sialon ceramics, and to define the influence of the properties of the coatings such as microhardness, adhesion, thickness and size of grains on the applicable properties of cutting edges covered by such coatings. Design/methodology/approach: The investigation studies pertaining to the following have been carried out: the structures of the substrates and coatings with the application of transmission electron microscopy; the structure and topography of coating surfaces with the use of electron scanning microscopy; chemical composition of the coatings using the GDOES and EDS methods; phase composition of the coatings using X-ray diffraction and grazing incident X-ray diffraction technique (GIXRD); grain size of the investigated coatings using Scherrer’s method; properties of the coatings including thickness, microhardness, adhesion and roughness; properties of the operating coatings in cutting trials. The models of artificial neural networks have been worked out which involve the dependencies between the durability of the cutting edge and properties of the coatings. Findings: Good adhesion of the coatings to the substrate from sintered carbides is connected with the diffusive mixing of the components of the coating and substrate. In the case of PVD coatings obtained on sialon ceramics, the highest adhesion to the substrate (Lc=53-112 N) has been demonstrated by the coatings containing the AlN phase of the hexagonal lattice having the same type of atomic (covalence) bond in the coating as in the ceramic substrate. The damage mechanism of the investigated coatings depends to a high degree on their adhesion to the substrate. The durability of cutting edges covered by the investigated coatings depends principally on the adhesion of the coatings to the substrate, and to a lesser degree on the other properties. Practical implications: While selecting a proper coating material on ceramic cutting edges, it is advisable to remember that the coatings having the same type of atomic bond as the ceramic substrate have higher adhesion to the substrate. Another relevant aspect of the research presented in the paper is the fact that the adhesion of the coatings contributes significantly to the durability of the cutting edge, whereas the microhardness of the coatings, their thickness and grain size have a slightly lower influence on the durability of the tool being coated. Originality/value: The paper presents the research involving the PVD and CVD coatings obtained on an unconventional substrate such as sialon ceramics. Furthermore, to define the influence of coating properties on the durability of cutting edges, artificial neural networks have been applied.

3

Mechanical and tribological properties of TiC-based composites for ED machining

Figiel P., Zimowski S., Klimczyk P., Dziwisz T., Jaworska L.

Archives of Materials Science and Engineering

|

2008

|

Vol. 33, nr 2

83-88

EN

Purpose: The goal of this work is comparative study of TiC-(Mo, Ni) composites with different TiC-phase content to obtain material with an optimal mechanical and tribological properties, which can be easy shaped by Electro Discharge Machining (EDM). Design/methodology/approach: Three variants of TiC-(Mo, Ni) composites with the different hardening phase to the bonding phase ratio were sintered in vacuum. The influence of the initial TiC hard phase content in the sintered composites on their mechanical and tribological properties as well as ED machinability were investigated. The density, Young modulus, hardness, fracture toughness were measured. Tribological tests were carried out conducted using "pin-on-disc" and "ball-on-disc" methods. Wire Electro Discharge Machining (WEDM) performance preliminary test were realised also. Findings: The microstructure of sintered TiC-(Mo, Ni) materials is characterized by a ring structure of carbides. Mechanical properties and wear resistance are better for samples with higher TiC content. All variants of investigated materials are characterized by good WED machinability. Research limitations/implications: Obtained materials are characterized by good mechanical, tribological and working properties but homogeneity of microstructure should be improved. Farther works will be continued also for limitation of the metallic phase content up to 5 vol. %. Practical implications: After additional technological evaluation tests, obtained materials could be used for the different parts of machines and wear components (e.g. nozzles, plungers) shaped by EDM. Originality/value: New type of TiC-metal bonded composite with high content of hard phase which could be shaped by EDM.

4

Influence of the method of heating/cooling moulds on the properties of injection moulding parts

Postawa P., Kwiatkowski D., Bociaga E.

Archives of Materials Science and Engineering

|

2008

|

Vol. 31, nr 2

121-124

EN

Purpose: The main purpose of carry out research was estimate the influence thermal conditions of the mould on properties of injection moulded parts. Design/methodology/approach: The properties of structure and mechanical properties of injection moulding parts were determined by many factors. One of them is thermal conditions of tool. Injection mould can be heated or cooling during the process and its depend which kind of polymer we produced and what properties we going to obtain. A few different cooling mould systems were presented in the article and disadvantages and advantages of each of them. Findings: The impact of thermal condition (cooling rate, mould temperature) on the structure and physical properties of injection moulded parts were present. Research limitations/implications: Research was limited to a few thermoplastics polymers. Practical implications: Received and presented results are useful from the point of the view of industrial applications and they are able to contribute to improvement parts obtained using injection moulding technology. Originality/value: Very original microscopic research carry out during cooling stage of polymer and crystallization process.

5

Kształtowanie własności eksploatacyjnych innowacyjnych obiektów technicznych wspomagane badaniami eksperymentalnymi.

Ruta R., Trzos M.

Zagadnienia Eksploatacji Maszyn

|

2006

|

Vol. 41, nr 4

109-119

PL

W artykule przedstawiono problem planowania eksperymentów w różnych sytuacjach badawczych związanych z opracowaniem innowacyjnych obiektów technicznych o zadanych właściwościach. Metody badań eksperymentalnych stanowią niezbędne narzędzie znajdujące zastosowanie nie tylko w końcowej weryfikacji własności eksploatacyjnych obiektu, ale także na etapie wyznaczania pożądanych wartości parametrów konstrukcyjnych i technologicznych. Szczególną uwagę poświęcono planowaniu układów eksperymentów w zależności od celu badań. Przedstawiono algorytmy planowania i realizacji badań oraz wyboru metod planowania układu eksperymentu. Opracowane algorytmy pozwalają na właściwe zaplanowanie i poprawną realizację badań. Algorytmy zostały zweryfikowane i zastosowane do zaplanowania badań eksperymentalnych w procesach kształtowania i oceny właściwości eksploatacyjnych konkretnych obiektów. W artykule przedstawiono przykład zastosowania algorytmów w procesie opracowania oleju o zadanych właściwościach smarnych.

EN

The article presents the issue of the planning experiments, which depends on research problem of developing of innovative technical objects characterized by requested properties. Experimental research methods are essential not only for the final verification of the object maintenance properties but also at the stages of the needed values of the constructional and technological parameters determination. The method of the experiments plan construction with special attention paid to the research objective is particularly discussed. The developed algorithms of planning and conductiong the experimental research that ensure correctness of the objects properties determination and verification are presented. The algorithms were verified and applied in processes of the actual objects' operational properties determination and verification. The article presents an example of the algorithms application in the process of the lubricant needed properties development.

6

New approach to study tribological properties of polymer materials. A case of car windshield wipers

Bielinski D. M., Glab P., Slusarski L.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 15, nr 1-2

71--78

EN

Purpose: Existing approach to tribology of polymer materials does not take into account their composition and structure. This paper presents the original analysis of friction characteristics, enabling an insight from the material engineering point of view. Design/methodology/approach: Apart friction also dissipation energy spectra have been analyzed. For transformation of friction fluctuations from the force into the frequency domain the FFT methodology has been applied. Parameters for evaluation of friction and wear have been proposed. Results of bench tests have been verified by examinations of wiper blades under conditions simulating real exploitation, adapting a system of car window cleaning. Power consumption by a driving engine has been monitored. Findings: Various kinds of modifications, influencing composition and structure of polymer materials have been studied. Ageing and wear resistance have been found to be the most important from the point of view of working properties of blades. They influence the efficiency of water removal from a car window. Research limitations/implications: Different blade designs have to be checked working under various conditions. Practical implications: A correlation between tribological properties and structure of polymer materials has to be taken into account at the stage of their compounding and processing. The proposed method for testing car windshield wiper blades is more appropriate than standards used so far, enabling quantitative assessment of products. Originality/value: The paper helps to understand materials engineering aspects of tribology. It is of potential value for producers of polymer parts.

7

Influence of magnetic field and inoculation on columnar structure transformation

Szajnar J., Wróbel T.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 17, nr 1-2

209--212

EN

Purpose: The main aim of investigations was the reduction of grain size and unification of structure for clean metal casting by introduction of small amount of inoculant, with rotate and impulse reverse magnetic field. Design/methodology/approach: Experimental plan was planed on the basis of statistical factor design on two levels for three variables: pulse frequency, current intensity and inoculant quantity. The output parameters: area of equiaxed crystals zone, average area of equiaxed crystal, average area of columnar crystal and most important equiaxed crystals zone content were calculated by computer program Multi Scan Base (program to processing and image analysis) after macroscopic metallographic research. Findings: The results of investigations and their analysis show relationship between area of equiaxial zone and pouring parameters: induction of magnetic field, pulse frequency of magnetic field and quantity of inoculant sort AlTi5B. Research limitations/implications: Towards lack of resolute relations between casting parameters and structure was selected statistical analysis to determine these relations using stepwise regression. In order to obtain accurate results, authors of this paper are going to extend the resarch range and use Zr and V to inoculation. Practical implications: The work presents refinement of structure methods which are particularly important in continuous and semi-continuous casting where products are used for plastic forming. Large columnar crystals zone result in forces extrusion rate reduction and during the ingot rolling delamination of external layers can occur. Thus, in some cases ingot skinning is needed, which rises the production costs. Originality/value: The value of this paper resides in coupling of two fineness of structure methods. The first method is internal factor – inoculation with Ti+B and the second method is external factor – influence of electromagnetic field on crystallization process.

8

Degradation of the cast steel parts working in power plant pipelines

Renowicz D., Hernas A., Cieśla M., Mutwil K.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 18, nr 1-2

219--222

EN

Purpose: Purpose of this paper is to identify the influence of loading history and the processes of material degradation on the initiation of cracking and on durability under creep and fatigue conditions. Design/methodology/approach: The aim of the research was to identify the properties of the material of the fittings cut out of a start-up pipeline connecting two OP-140 boilers with turbines, as well as to identify the reasons of failure of these parts after 100000 hours of operation. Results of the investigations were the basis of predicting the lifetime of machine parts and components of devices subjected to complex mechanical and thermal influence. Numerical simulation of work conditions was also performed. Problem of life assessment of the pipelines is currently the object of interest of many research centers. Findings: Due to extreme conditions of the start-up pipeline operation, its T-connections are subject to quick wear, and their properties determine the operational reliability and safety of the whole pipeline. For the reason it is necessary to verify the criteria of pipelines’ durability evaluation applied so far, based on the parameters characteristic of the creep process exclusively. Research limitations/implications: In the case discussed, i.e. a T-connection being a start-up pipeline part, the present criteria should be expanded with critical values describing fatigue/corrosion processes. Practical implications: The paper introduces the results of investigations of the 0.2C-1.2Cr-0.6Mo-0.3V cast steel used for parts of live steam pipelines working in power plants. Such parts include, e.g. T-connections. Originality/value: The paper show the possibilities of numerical models application.

9

Badanie własności eksploatacyjnych elektrod do napawania

Ślązak B.

Przegląd Spawalnictwa

|

2004

|

R. 76, nr 12

19-21

10

Ocena własności eksploatacyjnych powłok nanoszonych elektroiskrowo

Radek N., Ozimina D., Antoszewski B.

Przegląd Spawalnictwa

|

2003

|

R. 75, nr 11

15-18

11

Wpływ twardych warstw powierzchniowych typu TiN+(Ti, Al, Si)N+TiN na własności użytkowe cermetali narzędziowych i węglików spiekanych

Dobrzański L.A., Gołombek K.

Inżynieria Materiałowa

|

2003

|

R. XXIV, nr 6

449-452

PL

W pracy przedstawiono wyniki badań strukturalnych, własności mechanicznych oraz eksploatacyjnych przeciwzużyciowych powłok typu TiN+mono lub multi (Ti, Al, Si)N+TiN naniesionych w procesie PVD na podłoże z cermetali i węglików spiekanych. Przedstawiono badania strukturalne naniesionych powłok oraz podłoża w elektronowym mikroskopie skaningowym i na mikroskopie świetlnym. Oceny przyczepności pokryć naniesionych na węgliki spiekane i cermetale dokonano metodą zarysowania. Własności skrawne badanych materiałów określono na podstawie technologicznych prób ciągłego skrawania stali C45E. Jako kryterium oceny stopnia zużycia ostrza skrawającego przyjęto szerokość pasma zużycia na powierzchni przyłożenia narzędzia VBmax=0,2 mm, dla obróbki wykańczającej. Badania twardości podłoża i mikrotwardości naniesionych powłok przeprowadzono na ultramikrotwardościomierzu przy obciążeniu 70 mN. Dokonano również pomiarów chropowatości powierzchni przed naniesieniem powłok oraz po przeprowadzonym procesie PVD.

EN

The paper presents results of the structural examinations, tests of mechanical and working properties of thin anti-wear coatings of the TiN+mono or multi (Ti, Al, Si)N+TiN type, deposited in the PVD process onto the substrate from the tool cermets and sintered carbides. Structural examinations are presented of the applied coatings and their substrate made on the scanning electron microscope and on the light microscope. The lowest force Lc called the critical load was determined basing on the acoustic emission value (AE), at which loss of the coating adhesion to the substrate occurs. Cutting properties of the investigated materials were determined basing on the technological continuous cutting tests of the C45E steel. Width of the wear band on the tool flank VBmax=0,2 mm was assumed as the cutting edge wear criterion for finishing. Substrate hardness tests and microhardness tests of the deposited coatings were made on the ultramicrohardness tester at 70 mN load. Surface roughness tests were also made before depositing the coatings and after completing the PVD process.

12

Konstrukcyjne i materiałowe uwarunkowania procesów pękania elementów rurociągu eksploatowanego w przemyśle chemicznym.

Cieśla M., Mutwil K., Wojas M.

Inżynieria Materiałowa

|

1999

|

R. XX, nr 3-4

186-192

PL

W pracy poddano analizie konstrukcyjne i materiałowe uwarunkowania procesów pękania rurociągu eksploatowanego w przemyśle chemicznym. Badania przeprowadzono dla wybranych elementów rurociągu, takich jak trójnik i złącze spawane. Wykonano numeryczne obliczenia stanu wytężenia materiału rurociągu w ujęciu globalnym i lokalnym. Przeprowadzono badania metaloznawcze najbardziej zdegradowanych obszarów rurociągu. Omówiono wpływ przepływającego przez rurociąg czynnika (para-metan) i obciążeń cieplno-mechanicznych na obserwowane w badaniach procesy powstawania i wzrostu pęknięć. Zaproponowano wytyczne, dotrzymanie których pozwoli na poprawę własności eksploatacyjnych analizowanego obiektu.

EN

Structural and material conditions of cracking processes of a pipeline working in the chemical industry were analysed in the paper. The tests were performed for selected elements of the pipeline such as T-connection and a welded joint. Numerical calculations of the effort state of the pipeline material were made in global and local aspect. Structural metallurgy tests were conducted on the most degraded areas of the pipeline. An influence of an agent (vapour-methane) flowing through the pipeline and thermal-mechanical loads on the crack formation and growth processes observed in the tests were discused. Guidelines were suggested and complying with will ensures improvement of working properties of the analysed object.