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1

Warstwy powierzchniowe o szczególnych cechach : Mechanizm tworzenia i badania eksperymentalnie ich cech

Ozimina Dariusz, Madej Monika, Radek Norbert, Styp-Rekowski Michał

Obróbka Metalu

|

2023

|

nr 3

35--40

PL

W artykule przedstawiono rozważania dotyczące możliwości rozszerzenia wykorzystania obróbki elektroiskrowej. Wykazano, że obróbka elektroiskrowa może znaleźć zastosowania nie tylko bezpośrednio w procesach wytwórczych lecz także pośrednio - w procesach modyfikujących cechy użytkowe obrabianych elementów.

EN

In this paper considerations regarding the possibility of using electro-spark treatment were presented. It has been shown that electro-sparking can be used not only directly in manufacturing processes but also indirectly - in processes modifying the performance characteristics of the elements to be treated.

2

Tribological Properties of the Friction Pair with a-C:H Coating under the Conditions of Lubrication with 10W40 Biodegradable Engine Oil

Hadło Krystian, Lubas Janusz

Tribologia

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2022

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nr 2

15--22

EN

The present study discusses the influence of an a-C:H coating on the tribological parameters of sliding pairs under mixed friction. Using the PVD method, the a-C:H coating was formed on specimens made from AISI 4337 steel. The sliding friction and wear process was carried out on the pairs of AISI 4337 steel and SAE48 bearing alloy, which were lubricated with 10W40 biodegradable engine oil. The investigation showed significant differences in the friction coefficient and temperature in the tested pairs with the steel surface layer and the a-C:H coating. In the friction pairs with the a-C:H coating, the tested parameters of friction were higher than in pairs with the steel surface layer. The pairs with the a-C:H coating showed more intensive wear of the SAE-48 bearing alloy than those with a steel surface. The surface layer used in a friction pair leads to the deterioration of the lubricating properties of engine oil and reduces its resistance to scuffing.

PL

W pracy przedstawiono wpływ powłoki a-C:H na parametry tribologiczne par ciernych w warunkach tarcia mieszanego. Powłoka a-C:H została wytworzona na próbkach wykonanych ze stali AISI 4337 metodą PVD. Proces tarcia ślizgowego i zużycia realizowano w skojarzeniu stal AISI 4337 i stop łożyskowy SAE-48 smarowanych biodegradowalnym olejem silnikowym 10W40. Badania wykazały istotne różnice w wartości współczynnika tarcia i temperatury w badanych parach ze stalową warstwą wierzchnią i powłoką a-C:H. W parach z powłoką a-C:H rejestrowane parametry tarcia były wyższe niż w parach ze stalową warstwą wierzchnią. Pary z powłoką a-C:H wykazywały intensywniejsze zużycie stopu łożyskowego SAE-48 niż pary z powierzchnią stalową. Warstwa wierzchnia zastosowana w parze ciernej prowadzi do pogorszenia właściwości smarnych oleju silnikowego i zmniejsza jego odporność na zacieranie.

3

Effect of shop-primer coating on S235JR steel on MAG weldability

Çetinkaya Cemil, Akay Ali, Arabacı Uğur, Özdemir Uğur

Advances in Materials Science

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2022

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Vol. 22, nr 2(72)

49--63

EN

In this study, S235JR structural steel samples in uncoated condition and coated (shop-primer) in different thicknesses were welded by MAG (Metal Active Gas) welding method, and the effects of these applications on the mechanical and microstructure properties of the material were investigated. In the experimental studies, the first specimen group were used without any sandblasting and coating application, the second group specimens were sandblasted at Sa 2 ½ degree, and 25 μm, 50 μm, and 75 μm coatings were applied to the specimens in the other group. Surface conditions and coating thicknesses were selected as the variable parameters. With the examination of the radiography films, it was observed that the surface conditions affected the welded joint. As a result of the study, it was observed that altered coating thicknesses caused defects in the welding zone. It was determined that the coating thickness partially affected the mechanical properties, and the highest hardness values occurred in the weld zone in all samples. Relatively low values were obtained in tensile, bending and Charpy impact tests performed on sample groups with 75 μm coating thickness. The results were verified by the surface fracture, SEM, and EDS studies.

4

Modyfikowanie cech warstwy wierzchniej

Ozimina Dariusz, Radek Norbert

Obróbka Metalu

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2021

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nr 3

38--43

PL

Przedstawiono rozszerzony model jednej z metod tworzenia warstw wierzchnich – za pomocą obróbki elektroiskrowej. Zidentyfikowano zjawiska elementarne decydujące o efektach obróbki. Opisano mechanizmy powstawania poszczególnych stref warstwy wierzchniej oraz czynniki determinujące cechy tej warstwy. Przedstawiono także wyniki badań wstępnych, które potwierdziły możliwość wykorzystania obróbki elektroiskrowej do nadawania oczekiwanych własności i właściwości powierzchniom roboczym elementów maszyn współpracujących tarciowo. Uzyskane wyniki potwierdziły konieczność dalszej obróbki wytworzonych w taki sposób warstw wierzchnich. Powinno to przyczynić się do zwiększenia odporności na zużywanie elementów maszyn.

EN

In this paper one of the methods of creating surface layers - by means of electrospark treatment is presented. The elementary phenomena determining the processing effects were identified. Mechanisms of formation of individual zones of the surface layer and factors determining WW features are described. The results of experimental studies were also presented, which confirmed the possibility of using electrical discharge machining to impart the expected properties and characteristics to the working surfaces of frictionally cooperating machine elements. The results obtained confirmed the need for further mechanical treatment of the surface layers produced in this way. Modification of WW by the proposed method should contribute to a significant increase in the wear resistance of machine elements.

5

Comparative Tests of Shear Strength of Adhesive Lap Joints after Thermal Shocks

Kłonica Mariusz, Bielawski Radosław, Żokowski Mariusz

Advances in Science and Technology. Research Journal

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2021

|

Vol. 15, no 4

364--375

EN

This work presents the results of comparative tests for the determination of Young’s modulus and the static shear strength of adhesive lap joints, based on grade 316L steel. The tests also concerned the determination of the glass transition temperature of a certain adhesive composition: Epidian 57 epoxy resin with a 10% Z1 hardener content. The paper shows the test results for the surface free energy and selected surface roughness parameters, including photographs of the test specimens after destructive testing. The tests were comparative and performed on adhesive joints, with and without exposure to thermal cycling. The scope of the testing included a relatively short thermal cycling run of 500 cycles with a temperature variation of -40°C to +60°C. An analysis was carried out of the results from testing the static shear resistance of specimens manufactured using various methods of adhesive joint seasoning. The experimental test results were statistically processed in compliance with good research practice.

6

Experimental investigation of influence electrical discharge energy on the surface layer properties after EDM

Świercz Rafał, Holubek Radovan

Welding Technology Review

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2020

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R. 92, nr 5

7--13

EN

The modern industry looks for new technologies that lead to improving the durability of parts from difficult-to-cut materials. One of the main fields of study on manufacturing difficult-to-cut materials is using electrical discharge machining (EDM). In this work, the experimental investigation of the influence of discharge current and pulse time, which defines the discharge energy, on surface roughness and average white layer thickness, was carried out. The surface layers properties after machining have a key role in the durability of manufacturing parts. Conducted research indicates that an increase in current and pulse time leads to growing the diameter and power of the discharge channel. It's causing the generation of the roughness of greater height and distance between the individual vertices. The plasma stream generated as a result of electric discharges causes the melting and evaporation of the material locally, while micro streams of liquid metal "thrown" to the gap from craters re-solidify on the surface of the material. Experimental studies and their analysis indicate that the main factors influencing the surface topography and average thickness of the white layer after EDM is the discharge energy.

PL

Współczesny przemysł poszukuje nowych technologii, które prowadzą do zwiększenia trwałości części z trudnych do cięcia materiałów. Jednym z głównych kierunków studiów nad wytwarzaniem materiałów trudno skrawalnych jest obróbka elektroerozyjna (EDM). W pracy przeprowadzono eksperymentalne badanie wpływu prądu wyładowania oraz czasu impulsu określającego energię wyładowania na chropowatość powierzchni i średnią grubość białej warstwy. Właściwości warstw powierzchniowych po obróbce skrawaniem mają kluczową rolę w trwałości części produkcyjnych. Z przeprowadzonych badań wynika, że wzrost natężenia prądu i czasu impulsu prowadzi do zwiększenia średnicy i mocy kanału wyładowczego. Powoduje to generowanie nierówności o większej wysokości i odległości między poszczególnymi wierzchołkami. Strumień plazmy powstający w wyniku wyładowań elektrycznych powoduje miejscowe topienie i parowanie materiału, podczas gdy mikrostrumienie ciekłego metalu "wyrzucane" do szczeliny z kraterów ponownie krzepną na powierzchni materiału. Badania eksperymentalne i ich analiza wskazują, że głównymi czynnikami wpływającymi na topografię powierzchni i średnią grubość białej warstwy po EDM jest energia wyładowania.

7

The Effect of Cutting Tool Wear on the Rate of Corrosion Wear of a Machined Material

Bezjazychnyi Vyacheslav F., Pleskun Vladislav V.

Tribologia

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2020

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nr 1

5--11

PL

Zaproponowano sposób obliczeniowego oszacowania wpływu zużycia narzędzi skrawających na intensywność zużywania korozyjnego warstwy wierzchniej materiału obrabianego. Cechą charakterystyczną podejścia jest ocena stopnia zużycia korozyjnego w zależności od zużycia narzędzia, parametrów chropowatości powierzchni przedmiotu obrabianego i stopnia utwardzania warstwy wierzchniej na zimno, a także parametrów warunków obróbki technologicznej (parametrów skrawania, geometrii narzędzia skrawającego, właściwości obrabianego materiału i narzędzia).

EN

A possible variant for calculated estimation of the degree of the impact of the cutting tool wear on the value of the part’s surface layer wear obtained during processing with the edge tool, due to atmospheric corrosion, is presented. The feature is the evaluation of the wear rate and its numerical value depending on the tool wear, roughness parameters of the work piece surface, and the degree of cold hardening of the surface layer, as well as parameters of the technological machining conditions (cutting conditions, geometry of the tool cutting part, properties of the machined and the tool materials).

8

Numeryczne modelowanie warstw powierzchniowych na wybranych przykładach w aspekcie wyznaczania naprężeń resztkowych

Szymczyk Wiesław, Włodarczyk Joanna

Przegląd Mechaniczny

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2020

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nr 7-8

26--37

PL

Na warstwy powierzchniowe na elementach metalowych stosuje się różnorodne materiały. Warstwy powierzchniowe powstają zazwyczaj w warunkach wysokiej temperatury. Zasadniczy problem w warstwach powierzchniowych stanowią naprężenia resztkowe. Naprężenia resztkowe są pierwotną przyczyną zniszczenia warstwy powierzchniowej i ograniczenia trwałości elementu, na który ją naniesiono. Przyczyną powstania naprężeń własnych są znaczące różnice we właściwościach termomechanicznych łączonych faz materiałowych pokrycia i podłoża. W artykule przedstawiono zestawienie modeli numerycznych, które reprezentują zróżnicowane podejście do modelowania i wyznaczania wartości oraz rozkładów naprężeń resztkowych. Mogą one być stosowane przy zachowaniu świadomości konsekwencji dopuszczanych w nich uproszczeń oraz jakości symulacji uwzględniających określone cechy mikrostruktury.

EN

Various materials are used as a surface layers on metal parts. Surface layers are usually formed under high temperature conditions. Residual stresses are a major problem concerning surface layers. Residual stresses are the primary cause of the surface layer’s deterioration and limit the life span of the component on which it is applied. The cause of residual stresses is the significant differences in the thermomechanical properties of the combined material phases of the coating and substrate. The paper presents a list of numerical models which represent a different approach to modeling and determining values and distributions of residual stresses. They can be used with the awareness of the consequences of simplifications allowed in them and the quality of simulations taking into account specific microstructure features.

9

Skalowanie czujnika tensometrycznego za pomocą funkcji nieliniowej z wymuszeniem w wybranym punkcie jego charakterystyki

Filipowski Ryszard, Arasimowicz Anna, Lechniak Zbigniew, Zawora Józef

Obróbka Metalu

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2020

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nr 3

36--41

PL

Do oceny jakości obróbki zrealizowanej w procesach wytwórczych niezbędne są pomiary wielkości, które mogą stanowić kryteria oceny. Dokładność tych pomiarów zależy, m.in. od dokładności skalowania. W artykule przedstawiono nową, oryginalną procedurę skalowania czujnika tensometrycznego umożliwiającego precyzyjne określenie wartości naprężeń jakie zostają w warstwie wierzchniej po obróbce. Przeprowadzona weryfikacja doświadczalna wykazała poprawność procedury oraz pełną jej przydatność w badaniach technologicznych.

EN

For the evaluation of quality of machining realized in manufacturing processes measurements of quantities which may constitute evaluation criteria are necessary. The accuracy of these measurements depends on, among other from scaling accuracy of sensor. In this paper a new, original procedure for scaling a strain gauge sensor is described. It allows precise determination of values of stresses that remain in surface layer after machining. The experimental verification carried out showed the correctness of the procedure and its full usefulness in technological investigations.

10

Microstructure and Microhardness of Piston Alloy Al-10Si-2Cu Irradiated by Pulsed Electron Beam

Zaguliaev D., Konovalov S., Ivanov Y., Abaturova A., Leonov A.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

92--98

EN

The paper presents the research data on structure, phase composition, defect substructure state, and microhardness of surface layers in the piston alloy Al-10wt%Si-2wt%Cu irradiated by an electron beam with various energy densities and pulse times. An important finding to emerge from the study is that the processing by an electron beam with an energy density of 10 J/cm2 brings about slight surface melting, whereas a weak thermal impact of an electron beam hardly changes the phase composition. Once an energy density of an electron beam is set 30 J/cm2, intermetallic compounds dissolve and numerous micropores arise. Irradiating by an electron beam with an energy density of 50 J/cm2, randomly located microcracks are detected on the treated surface with no regard to a pulse time. A structure of high-speed cellular crystallization with cells from 500 to 600 nm forms in the surface layer. A thickness of the modified layer is related to a beam energy density. As a beam energy density goes up, a thickness of a high-speed cellular crystallization layer increases. Atoms of Si, Cu, Ni, as well as a small quantity of Fe and Mg are detected in the surface, in thin layers surrounding crystallization cells. In a layer 60-80 μm below the irradiated surface, in material between high-speed crystallization cells, there are Si atoms and an insignificant number of Cu atoms. An analysis of a deeper material part has shown a structure similar to the as cast alloy. A drop of microhardness – if compared with the as cast material – is reported at an energy density of 10 J/cm2 because an energy amount supplied by an electron beam to the alloy surface is insufficient for melting of the material and dissolution of the intermetallic phase. A raise of a beam energy density up to 20-50 J/cm2 causes a max increase of microhardness up to 1.13 GPa for 40 J/cm2, 50 μs, and up to 1.16 GPa for 40 J/cm2, 200 μs.

11

Strength of Joints with “Hi-Lok” Fasteners in Aircraft Safety Considerations

Kłonica Mariusz, Bielawski Radosław

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 4

87--93

EN

This paper reports on the results of strength tests of single-lap joints used in the aerospace industry with “Hi-Lok” fastener. The samples subjected to testing were made of EN-AW 2024 aluminium alloy and carbon composite. A part of the samples was additionally sealed with the use of Naftoseal MC-780 Class C sealant. The application of the MC-780 Class C sealant boosts the strength of a single lap joint of EN-AW 2024 T3 Al alloy and carbon composite. The strength test results were complemented with the analysis of selected 2D and 3D surface roughness parameters, and isometric images of the analysed surfaces. Additional information on the specimen surface quality was provided with photographic images taken with Keyence VHX-5000 microscope at x300 magnification. In the conclusion section of this paper, the study is summarised and its key findings are listed.

12

The influence of laser alloying of Ti13Nb13Zr on surface topography and properties

Tęczar P., Majkowska-Marzec Beata, Bartmański Michał

Advances in Materials Science

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2019

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Vol. 19, nr 1(59)

44--56

EN

The laser alloying is a continually developing surface treatment because of its significant and specific structuration of a surface. In particular, it is applied for Ti alloys, being now the most essential biomaterials` group for load-bearing implants. The present research was performed on the Ti13Nb13Zr alloy subject to laser modification in order to determine the treatment effects on surface topography and its some mechanical properties like nanohardness, Young's modulus, roughness. A pulse laser Nd:YAG was applied at three different laser pulse regimes: either 700 W, 1000 W or 1000 W treatment followed by 700 W modification at a pulse duration of 1 ms. The surface topography and morphology were examined using light microscopy and scanning electron microscopy with spectroscope of X-ray energy dispersion. The mechanical properties were determined by nanoindentation tests and surface roughness with a use of profilograph. The wettability was tested with a goniometer. The obtained results demonstrate complex behavior of the material surface: decrease in penetration distance and increase in hardness after first laser treatment, maintenance of this trend when machining using a higher laser pulse power, followed by an increase in penetration and decrease in hardness after additional laser treatment at lower power input, due to which a surface with fewer defects is obtained. The change in Young`s modulus follows the change in other mechanical properties, but not a change in roughness. Therefore, the observed hardening with the increase of the laser pulse power and then a small softening with the use of additional treatment with lower power can be attributed to some processes of remelting, diffusion and crystallization, sensitive to the previous surface state and heat energy flux. Despite that, the laser treatment always caused a significant hardening of the surface layer.

13

The effect of parameters burnishing rolling – pressuring process in aspect to technological quality surface layer of 316L stainless steel

Dyl T. C.

Journal of KONES

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2018

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Vol. 25, No. 1

75--81

EN

In the manufacturing of machine elements was important to technological quality products. In surface engineering one of the economic and ecological treatments used for technological properties were burnishing rolling – pressuring process. This is a surface plastic forming a local plastic deformation based on the overall impression given by smooth and hard tool. In production, engineering cylindrical outer surfaces (e.g. plugs propulsion shaft centrifugal pumps seawater) were finishing. You can therefore propose burnishing in exchange for abrasive machining. The article presents the influence of parameters for burnishing rolling – pressuring process on the degree of relative strain hardening and surface roughness reduction ratio. Burnishing process carried out for 316L stainless steels. After the experimental study, it was determined that there was an increase in hardness and a decrease in roughness of the top outer cylindrical layer of stainless steel, which can be applied to the centrifugal pump shafts ship. Important question to determine in the article of the research was to receive appropriate technological quality. The burnishing due the technological and economic aspect in the production of machine parts in exchange for the abrasive processing can be used. After the experiments, it was found that the technical parameters are influenced by the hardness and the roughness of the outer cylindrical surfaces and the material ratio curve a convex shaped, which, taking into account the load capacity of the surface will be directly affected by its resistance to wear and corrosion of the surface layer.

14

Surface Hardening of Nodular Cast Iron by GTAW Remelting

Orłowicz A. W., Trytek A., Korzeniowski M., Kupiec B.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 3

53--58

EN

The study reported in this paper was aimed at establishing the effect of values of parameters characterizing the process of superficial remelting of a nodular iron casting on the quantity of introduced heat, geometry of remeltings as well as parameter λ and hardness of cementite eutectic. The remelting process was carried out using GTAW method, at electric arc length of 3 mm in argon atmosphere, welding current intensities I = 50, 130, 210, and 300 A, and electric arc scanning speeds vs = 200, 400, and 800 mm/min. The measurements included estimation of the quantity of heat introduced to the casting in the electric arc-induced remelting process with the use of flow calorimeter. Widths and depths of remetlings were assessed with the use of metallographic method. As a result of fast solidification, cementite eutectic was obtained in remelted material in which, in the course of cooling down to ambient temperature, austenite was subject to partial transformation into martensite. To characterize the cementite eutectic, value of the structural parameter λ was assessed. Values of the parameter were similar for areas of occurrence of both fibrous and laminated eutectic. Remeltings were examined at half of their depths. Micro-hardness measurements were taken in the same areas. The established quantitative relationships may prove to be useful in practice for the purpose of predicting values of parameter λ and hardness of remeltings in studies aimed at improving resistance of cast-iron castings to abrasive wear.

15

Kinetics of Gases Emission from Surface Layers of Sand Moulds

Zych J., Mocek J., Kaźnica N.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 1

222--226

EN

Gas emission from casting moulds, cores and coatings applied for sand and permanent moulds is one of the fundamental reasons of casting defects occurrence. In the previous studies, gas emission was measured in two ways: normalized, in which the evolving gas volume was measured during heating of the moulding sand sample in a sealed flask, or by measuring the amount of gas from sand core (sample) which is produced during the pouring of liquid metal. After the pouring process the sand mould is heated very unequally, the most heated areas are layers adjacent to the liquid metal. The emission of gas is significantly larger from the surface layer than from the remaining ones. New, original method of measuring kinetics of gas emission from very thin layers of sand moulds heated by liquid metal developed by the authors is presented in the hereby paper. Description of this new method and the investigation results of kinetics of gas emission from moulding sand with furan and alkyd resin are shown. Liquid grey cast iron and Al-Si alloy were used as a heat source in the sand moulds. Comparison of the kinetics of gas emission of these two kinds of moulding sands filled with two different alloys was made. The momentary metal temperature in sand mould was assigned to the kinetics of gas emission, what creates a full view of the possibility of formation of casting defects of the gaseous origin. Moulding sand with alkyd resin is characterized by larger gas emission; however gases are emitted slower than in the case of moulding sands with furan resin. This new investigation method has a high repeatability and is the only one which gives a full view of phenomenon’s in the surface layer which determines quality of the casings. The obtained results are presented on several graphs and analyzed in detail. They have a great application value and can be used in the production of iron as well as light metal alloy castings.

16

Influence of engine oil on the friction and wear of a surface layer with boron

Lubas J., Szczypiński-Sala W.

Tribologia

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2017

|

nr 2

107--112

EN

The aim of the present work is to determine the influence of surface layers with boron and engine oil on the processes of friction and wear in friction pairs. The ring samples with a borided surface layer cooperated under test conditions with counterparts made with CuPb30 bearing alloy. During the tests, the friction pairs were lubricated with 15W/40 Lotos mineral oil and 5W/40 Lotos synthetic oil. The friction pairs lubricated by Lotos synthetic oil a generate stronger friction force and higher temperature in the contact area of friction pairs, as compared to the pairs lubricated by Lotos mineral oil. Lubrication of the friction pairs by mineral oil in the start-up phase causes faster stabilization of the friction conditions than in the case of lubrication by synthetic oil. The wear of bearing alloy was lower when lubricated by Lotos mineral oil than by Lotos synthetic oil. The process of friction in the contact area of the friction pair leads to the destruction of the lubricant and the reduction of its operational properties, especially at high temperatures.

PL

Celem pracy jest określenie wpływu warstwy wierzchniej z borem i oleju silnikowego na proces tarcia i zużycia w parach ciernych. Próbki pierścieniowe z borowaną warstwą powierzchni współpracowały w warunkach testowych z przeciwpróbkami wykonanymi ze stopu łożyskowego CuPb30. W trakcie testów pary cierne smarowano olejem mineralnym Lotos 15W/40 i olejem syntetyzującym Lotos 5W/40. Pary cierne smarowane olejem Lotos syntetyczny wytwarzają większe siły tarcia i wyższe temperatury w obszarze styku par ciernych w porównaniu z parami smarowanymi olejem Lotos mineralny. Smarowanie pary ciernej olejem Lotos mineralny w fazie rozruchu powoduje szybszą stabilizację warunków tarcia w obszarze styku niż w przypadku smarowania pary ciernej olejem syntetycznym. Zużycie stopu łożyskowego w warunkach smarowania olejem Lotos mineralny było niższe niż przy smarowaniu olejem Lotos syntetic. Proces tarcia w obszarze styku pary ciernej prowadzi do destrukcji czynnika smarnego i zmniejszenia jego właściwości eksploatacyjnych szczególnie w wyższych temperaturach.

17

Warstwy powierzchniowe w remontach urządzeń w PGE GiEK S.A. Oddział Elektrownia Bełchatów

Cecotka M.

Przegląd Spawalnictwa

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2017

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R. 89, nr 12

36--39

18

Comparison of selected properties of surface layer of Ti6Al4V titanium alloy after injection casting with and without suction

Szota M.

Archives of Materials Science and Engineering

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2017

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Vol. 87, nr 2

49--55

EN

Purpose: The paper presents the comparison of selected properties of surface layer between samples produced from Ti6Al4V titanium alloy by using injection casting with two options: injection with suction, injection without suction. Design/methodology/approach: Produced elements have been made of Ti6Al4V titanium alloy. The aim of the study was to compare selected properties of the surface layer of produced elements. The paper compares microstructure, microhardness and surface geometry after injection casting with and without suction. Additionally, all mentioned studies were carried out for input material. Findings: Research has shown that the use of innovative injection methods with and without suction for production of elements from Ti6Al4V titanium alloy affects on their structure and thus examined properties. It was observed that the elements produced by injection casting method have higher hardness values and lower development of surface,where sample produced by injection casting with suction has higher value of hardness and lower development of surface than sample produced by injection casting without suction. During the observation, a sample with suction has higher amount of a phase in cross-section surface layer than a sample without suction what can be caused because of the higher speed of heat transfer from produced element to the internal surface of the copper mould. Research limitations/implications: There can be a problem to make final elements with a more developed surface. Practical implications: Injection casting with suction can be used to produce small elements with different geometry from Ti6Al4V titanium alloy. Originality/value: The paper presents the possibility to improve selected properties of element surface produced by injection casting with suction and without suction.

19

Role of Sand Grains in Sorption Processes by Surface Layers of Components of Sand Moulds

Kaźnica N.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 1

87--92

EN

The results of researches of sorption processes of surface layers of components of sand moulds covered by protective coatings are presented in the hereby paper. Investigations comprised various types of sand grains of moulding sands with furan resin: silica sand, reclaimed sand and calcined in temperature of 700 oC silica sand. Two kinds of alcoholic protective coatings were used – zirconium and zirconium – graphite. Tests were performed under condition of a constant temperature within the range 30 – 35oC and high relative air humidity 75 - 80%. To analyze the role of sand grains in sorption processes quantitavie moisture sorption with use of gravimetric method and ultrasonic method were used in measurements. The tendency to moisture sorption of surface layers of sand moulds according to the different kinds of sand grains was specified. The effectiveness of protective action of coatings from moisture sorption was analyzed as well. Knowledge of the role of sand grains from the viewpoint of capacity for moisture sorption is important due to the surface casting defects occurrence. In particular that are defects of a gaseous origin caused by too high moisture content of moulds, especially in surface layers.

20

Application of FEM Analysis for Evaluation of the Stress and Deformation Distributions in the Top Layer of A390.0 Alloy During Friction

Wieszała R., Piątkowski J., Bąkowski H.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 1

228--234

EN

The paper presents an analysis of the effect of shape of primary silicon crystals on the sizes of stresses and deformations in a surface layer of A390.0 alloy by Finite Elements Method (FEM). Analysis of stereological characteristics of the studied alloy, performed based on a quantitative metallographic analysis in combination with a statistical analysis, was used for this purpose. The presented simulation tests showed not only the deposition depth of maximum stresses and strains, but also allowed for determining the aforementioned values depending on the shape of the silicon crystals. The studied material is intended for pistons of internal combustion engines, therefore the analysis of the surface layer corresponded to conditions during friction in a piston-cylinder system of an internal combustion engine having power of up to 100 kW. The obtained results showed important differences in the values of stresses and strains up to 15% between various shape of the silicon crystals. Crystals with sharp edges caused higher stresses and deformation locally than those with rounded shapes.