Wyniki wyszukiwania - BazTech

1

Tribological Testing of Environmentally Friendly Lubricants

Kowalski Marcin, Bernat Szymon, Kowalczyk Joanna, Radoń-Kobus Krystyna, Grabowski Paweł, Madej Monika

Tribologia

|

2023

|

nr 1

51--63

PL

W artykule porównano właściwości oleju mineralnego z olejem na bazie glicerolu i olejem na bazie oleju rzepakowego. Uzyskane wyniki badań wskazały, że współczynnik tarcia dla oleju mineralnego wykazał zbliżoną charakterystykę dla obu obciążeń (25 N/ 50 N), również minimalne zmiany zaobserwowano dla oleju na bazie oleju rzepakowego. Natomiast największą różnicę uzyskano dla oleju na bazie glicerolu i wody, gdzie współczynnik tarcia wzrósł o ponad 23% dla obciążenia 50 N w porównaniu z obciążenie m 25 N. Przeprowadzone badania wskazują na bardzo dobrą charakterystykę olejów na bazie oleju rzepakowego oraz oleju na bazie glicerolu i wody wraz z dodatkami zmniejszającymi tarcie w zależności od przyłożonego obciążenia. Dla niż szych obciążeń bardzo dobre właściwości przeciwzużyciowe posiada olej na bazie glicerolu i wody, zaś dla wyższych olej na bazie oleju rzepakowego. Zatem w odpowiednich warunkach oleje przyjazne środowisku mają zbliżone lub lepsze właściwości smarne aniżeli toksyczne wysoko „zdodatkowane” oleje mineralne. Tym samym posiadają potencjał zastąpienia powszechnie stosowanego oleju mineralnego.

EN

This paper compares the properties of mineral oil with glycerol and water-based oil, and rapeseed-based oil. The obtained research results showed that the friction coefficient for mineral oil has similar characteristics for both loads (25 N/50 N). Minimal differences were also observed for the rapeseed-based oil. However, the most significant difference was obtained for oil based on glycerol and water, where the friction coefficient increased by more than 23% under the load of 50 N compared to 25 N. The tests showed very good characteristics of the oils based on rapeseed oil and the oil based on glycerol and water with additives reducing friction, depending on the applied load. For lower loads, the oil based on glycerol and water has very good anti-wear properties, whereas the oil based on rapeseed oil has very good anti-wear properties for higher loads. Thus, environmentally friendly oils have similar or better lubricating properties under appropriate conditions than toxic oils with high additive contents. Hence, they have the potential to replace the commonly used mineral oil.

2

Laser surface texturing: characteristics and applications

Kalinowski Artur, Radek Norbert, Orman Łukasz, Pietraszek Jacek, Szczepaniak Marcin, Bronček Jozef

System Safety : Human - Technical Facility - Environment

|

2023

|

Vol. 5, iss. 1

240--248

EN

Laser surface texturing (LST) has emerged as a versatile and efficient technique for modifying surface properties across various materials. This paper provides an analysis of the characteristics and diverse applications of laser surface texturing. The paper begins by explaining the fundamental principles underlying LST, highlighting the mechanisms involved in material interaction and the resultant surface modifications. It explores the influence of laser parameters such as pulse duration, energy density, and wavelength on the texturing process, emphasizes their impact on surface morphology, roughness, and topographical features. Furthermore, this paper delves into the wide-ranging applications of LST across different industries and fields. It examines how LST enhances surface functionalities, including improvements in tribological properties, wettability, friction reduction, and biocompatibility. Additionally, the utilization of LST for creating microstructures enabling advanced functionalities in optics, electronics, biomedical devices, and energy harvesting systems is discussed. Moreover, the challenges and future directions in LST technology are highlighted, which encompass advances in precision, scalability, and integration of LST with other manufacturing processes. The potential environmental implications and economic feasibility of LST are also discussed.

3

Development and Tribological Characterization of Semi-Metallic Brake pads for Automotive Applications

Esteem P L, Ramalingam Vaira Vignesh, Kasi Rajesh Kannan, Ramasamy Padmanaban

Archiwum Motoryzacji

|

2023

|

Vol. 102, nr 4

5--25

EN

Semi-metallic brake pads are quite a good choice for performance-driven automotive industries, because of improved braking performance in a more comprehensive range of temperatures. In this study, a semi-metallic brake pad is fabricated through a powder metallurgy processing technique with two compositions of powders with a different weight ratio of Copper (Cu), Iron (Fe), flash, Aluminum oxide (Al2O3), Barium sulfate (BaSO4), Phenolic resin, Low-Density Polyethylene (LDPE), Graphite for automotive application. A well-distributed composition was indicated by the microstructure, which exhibited a uniform dispersion of hard particles throughout the matrix. BP-20Cu-20Fe specimen exhibited a high hardness value of 171Hv. Under higher loads of 70 N, the specimen BP-20Cu-20Fe showed excellent wear resistance, with a low wear rate of 1.072×10-6 g/Nm. On the other hand, specimen BP-20Cu-20Fe showed a notable 35% increase in friction coefficient when the load was increased from 30 N to 70 N.The surface morphology, elemental distribution, and worn surface features and characteristics are examined using advanced instrumental techniques.

4

The Burnishing Process of the Duplex Cast Steel in Aspect of Improving the Tribological Properties

Stradomski G. E., Fik Joanna, Rydz Dariusz

Archives of Foundry Engineering

|

2023

|

Vol. 23, iss. 2

51--57

EN

Duplex cast steel it is a material with great potential. The properties of this material have contributed to its wide application in many industrial sectors, for example: oil extraction, printing, petrochemical industry, energy - flue gas desulphurization systems, seawater desalination plants, shipbuilding industry. The article presents the results of tribological tests following the static pressure roller burnishing (SPRB) process of GX2CrNiMoN22-5-3 duplex cast steel. The tests provided a basis for assessing the effect of the burnishing parameters on tribological properties of that material. The issue is important because the authors focused their research on duplex cast steels grade that are not containing copper. The article presents part of the research concerning the influence of the burnishing process on the properties of the duplex steel surface layer. Copper in duplex steels affects many areas one of them is the plastic properties. Its absence also reduces castability. Because of that it is reasonable to determine to what extent the properties of the surface layer of copper-free duplex cast steel grades can be shaped in burnishing process.

5

Surface Topography and Tribological Properties of Cutting Tool Coatings

Niemczewska-Wójcik Magdalena, Madej Monika

Advances in Science and Technology. Research Journal

|

2023

|

Vol. 17, no 6

39--48

EN

The surface topography formed during the technological process has an influence on the wear characteristics and modifies the surface topography of friction components during the operation process, including cutting tools. It is therefore important to carry out research to find the best material and construction solutions to increase their durability and reliability. The research and analysis covered selected coatings (TiN, TiCN, TiAlN) applied to cutting tools for their anti-wear properties. The coatings were obtained through physical vapour deposition PVD. For the purpose of evaluating the tribological properties of the coatings, friction-wear tests were carried out in rotary motion on a ball-on-disc device (ball made of 100 Cr6 steel, discs made of SW7M steel coated with selected coatings) at a constant load (10N), under coolant lubrication conditions. Investigations of the surface topography before and after tribological tests were carried out on a confocal microscope. The friction coefficient and the amount of wear (wear track) of the coatings were shown to vary under the same operating conditions. The highest friction coefficient was obtained for the TiCN coating (0.199), while the lowest for the TiN coating (0.144) – the surface topography of the balls deteriorated (parameters Sq, Sz, Ssk, Sku increased in value). The highest linear wear (281.1 µm) was obtained for the TiAlN coating (the coating was torn halfway through the test), where the ball surface topography has improved (lowered values of parameters Sq, Sz, Ssk, Sku, Spd, Spc).

6

Abrasive Wear Mechanisms of S235JR, S355J2, C45, AISI 304, and Hardox 500 Steels Tested Using Garnet, Corundum and Carborundum Abrasives

Szala Mirosław, Szafran Michał, Matijošius Jonas, Drozd Kazimierz

Advances in Science and Technology. Research Journal

|

2023

|

Vol. 17, no 2

147--160

EN

Wear resistance is one of the main indicators of the reliability of machine parts. The selection of wear-resistant material should consider the operational environment and specific types of abrasive material. The steel abrasive wear resistance depends not only on its hardness and microstructure but also on the abrasive material's properties, such as hardness and particle morphology. This work aimed to determine abrasion wear mechanisms of a set of steels, i.e., S235, S355, C45, AISI 304 and Hardox 500, abraded by different types of grit i.e. garnet, corundum and carborundum. The abrasion tests were conducted using T-07 tribometer (rubber wheel method). Wear traces were examined with a scanning electron microscope (SEM), and a contact profilometer. SEM analysis revealed that apart from Hardox 500, ploughing and microfatigue were the dominant wear mechanisms. Microcutting was the main wear mechanism for Hardox 500 tested with carborundum (SiC). The highest mass loss was usually obtained for carborundum. The lowest wear resistance in garnet and carborundum was obtained for the S235JR and S235J2 steels and Hardox 500 tested with corundum. The effect of steel microstructure on the wear mechanism has been confirmed. AISI 304 austenitic steel abraded by carborundum grit, presented outstanding roughness parameters: Ra, Rz, RSm, Rk, Rvk and Rpk than other steels tested with carborundum. Steel hardness affects the morphology of the wear trace reducing the Ra and Rz roughness parameters. The effect of abrasive hardness and grain morphology on abraded surfaces has been stated. Contrary to fine grains of the hardest carborundum, coarse garnet grains caused high roughness parameters (Rk, Rpk and Rvk) determined in wear trace.

7

Phenomenological model of cavitation erosion of nitrogen ion implanted HIPed Stellite 6

Szala Mirosław

Advances in Materials Science

|

2023

|

Vol. 23, nr 1(75)

98--109

EN

Stellites are a group of Co-Cr-C-W/Mo-containing alloys showing outstanding behavior under cavitation erosion (CE) operational conditions. The process of ion implantation can improve the CE resistance of metal alloys. This work presents the elaborated original phenomenological model of CE of nitrogen ion implanted HIP-consolidated (Hot Isostatically Pressed) cobalt alloy grade Stellite 6. The ultrasonic vibratory test rig was used for CE testing. The nitrogen ion implantation with 120 keV and fluence of 5 × 1016 N+/cm−2 improves HIPed Stellite 6 cavitation erosion resistance two times. Ion-implanted HIPed Stellite 6 has more than ten times higher CE resistance than the reference AISI 304 stainless steel sample. Comparative analysis of AFM, SEM and XRD results done at different test intervals reveals the kinetic of CE process. The model includes the surface roughness development and clarifies the meaning of cobalt-based matrix phase transformations under the nitrogen ion implantation and cavitation loads. Ion implantation modifies the cavitation erosion mechanisms of HIPed Stellite 6. The CE of unimplanted alloy starts on material loss initiated at the carbides/matrix interfaces. Deterioration starts with cobalt matrix plastic deformation, weakening the carbides restraint in the metallic matrix. Then, the cobalt-based matrix and further hard carbides are removed. Finally, a deformed cobalt matrix undergoes cracking, accelerating material removal and formation of pits and craters' growth. The nitrogen ion implantation facilitates ɛ (hcp—hexagonal close-packed)) → γ (fcc—face-centered cubic) phase transformation, which further is reversed due to cavitation loads, i.e., CE induces the γ → ɛ martensitic phase transformation of the cobalt-based matrix. This phenomenon successfully limits carbide removal by consuming the cavitation loads for martensitic transformation at the initial stages of erosion. The CE incubation stage for ion implanted HIPed Stellite 6 lasts longer than for unimplanted due to the higher initial content of γ phase. Moreover, this phase slows the erosion rate by restraining carbides in cobalt-based matrix, facilitating strain-induced martensitic transformation and preventing the surface from severe material loss.

8

Regression Using Machine Learning and Neural Networks for Studying Tribological Properties of Wear-Resistant Layers

Malinowski Paweł, Kasińska Justyna

Tribologia

|

2022

|

nr 1

57--64

EN

Artificial intelligence is becoming commonplace in various research and industrial fields. In tribology, various statistical and predictive methods allow an analysis of numerical data in the form of tribological characteristics and surface structure geometry, to mention just two examples. With machine learning algorithms and neural network models, continuous values can be predicted (regression), and individual groups can be classified. In this article, we review the machine learning and neural networks application to the analysis of research results in a broad context. Additionally, a case study is presented for selected machine learning tools based on tribological tests of padding welds, from which the tribological characteristics (friction coefficient, linear wear) and wear indicators (maximum wear depth, wear area) were determined. The study results were used in exploratory data analysis to establish the correlation trends between selected parameters. They can also be the basis for regression analysis using machine learning algorithms and neural networks. The article presents a case study using these approaches in the tribological context and shows their ability to accurately and effectively predict selected tribological characteristics.

PL

Zastosowanie sztucznej inteligencji w różnych dziedzinach nauki i przemysłu jest coraz bardziej powszechne. Duża różnorodność metod statystycznych i predykcyjnych umożliwia użycie ich również w tribologii. Analiza danych liczbowych w postaci charakterystyk tribologicznych, struktury geometrycznej powierzchni oraz wielu innych wymaga zastosowania narzędzi informatycznych oraz statystycznych. Wykorzystanie algorytmów uczenia maszynowego i budowanie modelu sieci neuronowej umożliwi prognozowanie wartości ciągłych (regresja) oraz klasyfikowanie poszczególnych grup. W artykule autorzy dokonują przeglądu możliwości aplikacyjnych algorytmów uczenia maszynowego i sieci neuronowych do analizy wyników badań w szerokim kontekście. Dodatkowo zaprezentowano studium przypadku dla wybranych narzędzi uczenia maszynowego na podstawie przykładowych badań tribologicznych napoin, dla których przeprowadzono testy, w których wyznaczono charakterystyki tribologiczne (współczynnik tarcia, zużycie liniowe) oraz wskaźniki zużycia (maksymalna głębokość wytarcia, pole wytarcia). Wyniki badań były podstawą do przeprowadzenia analizy eksploracyjnej i posłużyły do wykazania korelacji pomiędzy wybranymi parametrami. Autorzy przekonują, że mogą one być podstawą do analizy regresji z wykorzystaniem algorytmów uczenia maszynowego i sieci neuronowych. W artykule zaprezentowano studium przypadku z wykorzystaniem tych podejść w kontekście tribologicznym oraz pokazano ich zdolność do dokładnego i skutecznego przewidywania wybranych charakterystyk tribologicznych.

9

Properties of Al2O3 Ceramic Coatings Applied by ALD Method on 100Cr6 Steel

Radoń-Kobus Krystyna, Madej Monika

Tribologia

|

2022

|

nr 2

45--53

EN

The purpose of the paper was to assess the morphology, chemical composition, geometric surface structure and contact angle, as well as to analyse the tribological properties of Al2O3 coatings deposited on 100Cr6 steel using the technique of atomic layers ALD. Al2O3 coatings were selected due to their tribological properties, adhesion to the substrate and hardness. Tribological tests were performed in a reciprocating motion in a ballon-disc combination, with a counter-specimen of 100Cr6 steel, under the conditions of technically dry friction. Surface morphology was observed under a scanning microscope, and an EDS analyser enabled the performance of an analysis of the chemical composition of the samples. Wetting of the surface of the Al2O3 coating was determined by means of an optical strain gauge. The geometric surface structure before and after the tribological tests was analysed by means of a confocal microscope with an interferometric mode. The tests proved that during technically dry friction, the average coefficient of friction for the Al2O3 coating is lower by approximately 30% than for 100Cr6 steel. The tested coatings are characterised by hydrophobicity.

PL

Celem pracy była ocena morfologii, składu chemicznego, struktury geometrycznej powierzchni, kąta zwilżania oraz analiza właściwości tribologicznych powłok Al2O3 osadzanych na stali 100Cr6 techniką warstw atomowych ALD. Powłoki Al2O3 wytypowano ze względu na ich właściwości tribologiczne, adhezję do podłoża oraz twardość. Testy tribologiczne przeprowadzono w ruchu posuwisto-zwrotnym w skojarzeniu kula–tarcza z przeciwpróbką ze stali 100Cr6 w warunkach tarcia technicznie suchego. Na mikroskopie skaningowym obserwowano morfologię powierzchni, a analizator EDS umożliwił przeprowadzenie analizy składu chemicznego próbek. Przy pomocy tensjometru optycznego określono zwilżalność powierzchni powłoki Al2O3. Strukturę geometryczną powierzchni przed i po testach tribologicznych analizowano za pomocą mikroskopu konfokalnego z trybem interferometrycznym. Testy wykazały, że podczas tarcia technicznie suchego średni współczynnik tarcia dla powłoki Al2O3 jest około 30% mniejszy niż dla stali 100Cr<6. Badane powłoki charakteryzują się hydrofobowością.

10

Analysis of the Influence of Hexagonal Boron Nitride on Tribological Properties of Grease

Senyk Szymon, Kałdoński Tadeusz

Tribologia

|

2022

|

nr 3

101--112

EN

The article discusses the problem of using hexagonal boron nitride (h-BN) as a grease additive. The literature on the subject was analysed in terms of greases into which hexagonal boron nitride was added. Particular attention was paid to the nano h-BN, due to the topicality of this topic and the potential of nano-additives to lubricants noted in published scientific studies. It was found that in order to indicate the regularities describing the tribological interaction of hexagonal boron nitride, detailed studies and an analysis of its properties are required. The important factors determining the application of this additive include particle size distribution, morphology, specific surface area, and porosity. The mentioned properties were determined for four samples of hexagonal boron nitride, which were also objects of tribological experiments. For this purpose, a scanning electron microscope (SEM) and XRD method were used, and low-temperature adsorption isotherms were determined. The research on the influence of h-BN on the lubricity properties of lithium grease was carried out on a four-ball apparatus. Possible mechanisms of interaction of different types of h-BN in the friction zone were identified using the information collected on their important properties. Based on the results of the research, it was found that the use of nano h-BN in the discussed context seems promising.

PL

W artykule podjęto problematykę zastosowania heksagonalnego azotku boru (h-BN) jako dodatku do smarów plastycznych. Przeprowadzono analizę literatury tematu pod kątem smarów plastycznych, do których wprowadzano heksagonalny azotek boru. Szczególną uwagę zwrócono na nanodmianę h-BN, z uwagi na aktualność tej tematyki i odnotowywany w opublikowanych badaniach naukowych potencjał nanododatków do środków smarnych. Stwierdzono, że aby wskazać prawidłowości opisujące tribologiczne oddziaływanie heksagonalnego azotku boru wymagane są szczegółowe badania i analiza jego właściwości. Do istotnych czynników determinujących opisywane zastosowanie tego dodatku zaliczono: rozkład rozmiarów jego cząstek, ich morfologię, powierzchnię właściwą, a także porowatość. Wymienione właściwości określono dla czterech próbek heksagonalnego azotku boru, które były jednocześnie obiektami eksperymentów tribologicznych. Wykorzystano w tym celu skaningowy mikroskop elektronowy (SEM), metodę dyfrakcji rentgenowskiej (XRD) oraz wyznaczono niskotemperaturowe izotermy adsorpcji. Badania wpływu h-BN na właściwości smarnościowe litowego smaru plastycznego przeprowadzono na aparacie czterokulowym. Zidentyfikowano możliwe mechanizmy oddziaływania różnych typów h-BN w strefie tarcia, wykorzystując przy tym zgromadzone informacje dotyczące ich istotnych właściwości. Na podstawie wyników przeprowadzonych badań stwierdzono, że zastosowanie nano h-BN w omawianym kontekście wydaje się perspektywiczne.

11

A Contribution to the Knowledge of Synergy in Tribology Systems

Tyczewski Przemysław, Zwierzycki Wiesław, Stachowiak Arkadiusz, Ulbrich Dariusz

Tribologia

|

2022

|

nr 4

95--101

EN

The article contains information about the knowledge of synergism in tribology systems. Two examples of analyses of synergism in tribology systems are presented in the article. In the first example, the interaction coefficient (synergy coefficient) was used to evaluate a set of engine and gear oils composed of special lubricating (surface-active) additives to improve the galling load – a measure of boundary layer strength, evaluated on a 4-ball apparatus. Using the interaction coefficient, a 12-element set of oils (compositions) was "separated" into three groups: synergism with additives (KS>1), sometimes strong, at KS=2, neutral interaction (KN=1), antagonism with additives (KA<1). Analysis of test results using the synergism coefficient also makes it possible to select the optimal additive concentration in commercial oil. In the second case, a three-factor system was analysed, in which the resultant (undesirable) characteristic was a measure of mechanical corrosion-abrasive wear of metal parts. In specially designed experiments, the components of total wear derived from the three underlying factors (mechanical, corrosion and environmental), and the interaction between them was determined. The contribution of the sum component of the mechanical-corrosion-abrasive interactions was found to range from 40 to 50% of the total wear (at 50%, there is a strong synergism KS=1).

PL

Artykuł zawiera informacje mające uzupełnić wiedzę o synergizmie w systemach tribologicznych. Przedstawiono dwa przykłady analiz synergizmu w układach tribologicznych. W pierwszym z przykładów posłużono się współczynnikiem oddziaływania (współczynnikiem synergii) do oceny zbioru olejów silnikowych i przekładniowych, które komponowano ze specjalnymi dodatkami smarnościowymi (aktywnymi powierzchniowo) w celu poprawy tzw. obciążenia zatarcia – miary wytrzymałości warstwy granicznej, ocenianej na aparacie 4-kulowym. Posługując się współczynnikiem oddziaływania rozdzielono 12-elementowy zbiór olejów (kompozycje) na trzy grupy wykazujące: synergizm z dodatkami (KS>1), niekiedy silny, przy KS=2, współdziałanie neutralne (KN=1), antagonizm z dodatkami (KA<1). Analiza wyników badań przy pomocy współczynnika synergizmu pozwala również dobrać optymalne stężenie dodatku w oleju handlowym. W drugim z przypadków analizowano system trójczynnikowy, w którym cechą wynikową (niepożądaną) była miara zużycia mechaniczno-korozyjno-ściernego elementów metalowych. W specjalnie zaprojektowanych eksperymentach wyznaczono składowe zużycia całkowitego pochodzące od trzech czynników bazowych (mechanicznego, korozyjnego i środowiskowego) oraz od interakcji między nimi. Stwierdzono, że udział składowej sumarycznej odziaływań interakcyjnych mechaniczno-ścierno-korozyjnych wynosi od 40 do 50% zużycia całkowitego (przy 50% występuje silny synergizm KS=1).

12

Evaluation of Wear Mechanisms of Graphites Used for Crystallisers for Continuous Casting

Brudny Anna, Kulasa Joanna, Juszczyk Barbara, Myalski Jerzy, Roskosz Stanisław, Wycisk R., Kwaśniewski Paweł, Strzępek Paweł, Poręba Marek

Archives of Foundry Engineering

|

2022

|

Vol. 22, iss. 4

109--115

EN

This paper presents the results of research concerning the evaluation of tribological properties of graphite materials used, among others, for crystallisers for continuous casting of non-ferrous metals and their alloys. Graphite materials differing not only in their physical properties but also in the technology of their production were selected from a wide range of commercially available products. Wear resistance investigations of the tested graphite materials were carried out on a pin-on-disc tribometer under technically dry friction conditions on a sliding distance of 1000 m. A constant load but variable speed was used in the tests. The mean value of the coefficient of friction and the wear of the material were determined based on the tribological tests carried out. It was observed that as the speed increases, the average value of the coefficient of friction decreases, while the wear increases. A microstructural analysis of the wear track showed that the friction mechanism depends mainly on the graphite formation technology, which is related to the microstructure of the tested materials, and to a lesser extent to their physical and mechanical properties. Varying the speed values made it possible to trace changes in the wear mechanism, on the basis of which it is possible to predict the durability and reliability of graphite crystalliser operation.

13

Effect of Water Absorption on Tribological Properties of Thermoplastics Matrix Composites Reinforced with Glass Fibres

Walczak Mariusz, Szala Mirosław, Pieniak Daniel

Advances in Science and Technology. Research Journal

|

2022

|

Vol. 16, no 2

232--239

EN

The present work investigated the water absorption of thermoplastic matrix composites and their effect on tribological behaviour. Four thermoplastic composites were researched based on Polyamide 6 and Polyamide 66 matrix reinforced with glass fibres. The composites fabricated using the injection moulding technique were immersed in distilled water at room temperature for a water absorption test for 14 days. Dry sliding wear was conducted using a pin-on-disc trbiotester. The coefficient of friction (COF) and the wear rate (K) was determined. The sliding trace was analyzed using a scanning electron microscope (SEM) to reveal the sliding wear mechanism of composites. Studies have shown that polyamide PA6 based composites are less prone to absorb water than PA66 matrix. In addition, the composites richer in fibreglass exhibit lower water absorption. Tribological results indicated that polymer composites showed higher COF and K after water absorption testing. Mean COF and K were in the range of 0.071÷0.321 and 2.51∙10-6÷1.81∙10-4 mm3N-1m-1, respectively. Wear traces SEM analysis revealed that untreated samples are characterized by less intense abrasive and adhesive wear mode than the hydrated polymers. Besides, the degradation process took place primarily at the polymer matrix-fibreglass interfaces.

14

Tribological wear of Fe-Al coatings applied by gas detonation spraying

Chrostek Tomasz

Technical Sciences / University of Warmia and Mazury in Olsztyn

|

2021

|

nr 24(1)

245--256

EN

Comparative tests of gas detonation (GDS) coatings were carried out in order to investigate the influence of spraying parameters on abrasive wear under dry friction conditions. The tests were carried out using the pin-on-disc (PoD) method at room temperature. The microstructure of the coatings was analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM/EDS) methods. The results showed that with certain parameters of the GDS process, the main phase of the produced coatings is the FeAl phase with the participation of thin oxide layers, mainly Al2O3. The tribological tests proved that the coatings sprayed with the shorter barrel of the GDS gun showed higher wear resistance. The coefficient of friction was slightly lower in the case of coatings sprayed with the longer barrel of the GDS gun. During dry friction, oxide layers form on the surface, which act as a solid lubricant. The load applied to the samples during the tests causes shear stresses, thus increasing the wear of the coatings. During friction, the surface of the coatings is subjected to alternating tensile and compressive stresses, which lead to delamination and is the main wear mechanism of the coatings.

15

Badanie tribologiczne oraz przyczepność powłok natryskiwanych płomieniowo poddźwiękowo proszkowo

Rzeźnikiewicz Agnieszka

Stal, Metale & Nowe Technologie

|

2021

|

nr 9-10

89--92

PL

Dynamiczny rozwój techniki w ostatnich kilkudziesięciu latach postawił przed technologią natryskiwania nowe wyzwanie – poszukiwano procesu nakładania powłok, który nie będzie w znaczący sposób oddziaływał cieplnie na podłoże. Większość warstw natryskiwanych przylega do podłoża za pomocą sił mechanicznych, dlatego też jednym z najważniejszych czynników podczas procesu natryskiwania jest odpowiednie przygotowanie podłoża polegające na oczyszczeniu powierzchni oraz nadaniu jej odpowiedniej chropowatości.

EN

The dynamic technological development in the last few decades has posed a new challenge to the spraying technology – a coating process has been sought that will not have a significant thermal impact on the substrate. Most spray layers adhere to the substrate by mechanical forces, therefore one of the most important factors during the spraying process is the proper preparation of the substrate by cleaning its surface and roughening it suitably.

16

Szybkobieżne łożysko ślizgowe z tocznym wspomaganiem rozruchu (koncepcja łożyska kombinowanego)

Mikuła Jarosław, Mikuła Stanisław, Strzelecki Stanisław

Przegląd Mechaniczny

|

2021

|

nr 4

23--27

PL

W artykule przedstawiono problemy występujące podczas rozruchu i wybiegu łożysk ślizgowych, zwłaszcza szybkoobrotowych. Sformułowano wytyczne dla zmniejszenia oporów rozruchu i zwiększenia efektywności energetycznej łożyskowań ślizgowych pracujących przy dużych i bardzo dużych prędkościach obrotowych. Autorska koncepcja konstrukcji łożyska ślizgowego poprzecznego zapewnia wydatne zmniejszenie oporów rozruchowych przy zwiększonej trwałości eksploatacyjnej. Cel osiągnięto przez zastosowanie wspomaganego rozruchu ślizgowego łożyska ze smarowaniem hydrodynamicznym łożyskiem tocznym, wyłączanym z pracy po uzyskaniu założonej prędkości obrotowej. Wspomagające łożysko toczne jest automatycznie włączane do pracy podczas wybiegu. Opisane rozwiązanie pozwala na zmniejszenie czasu rozruchu oraz zabezpiecza przed pracą w warunkach niedostatecznej nośności filmu smarowego, która występuje podczas rozruchu i wybiegu; umożliwione jest również zastosowanie cieczy smarnych o zdecydowanie niższej lepkości, w tym emulsji olejowo-wodnych i czystej wody. Pozwala to na uzyskanie wielu korzystnych cech użytkowych.

EN

This paper presents the problems occurring during the start-on and slowing-down of journal bearings, and particularly high-speed bearings. The directives were formulated to decrease in start-up resistance and the increase in the power effectiveness of journal bearings systems operating at the high and very high rotational speeds. Author’s idea of the design of radial journal bearing assures the decrease in the start-on resistance at the larger exploitation durability. This task was achieved by the application of hydrodynamic journal bearing added by the rolling bearing that was switched off after achieving the assumed rotational speed. The added rolling bearing is automatically switched on during the slowing-down the device. The described design solution allows decreasing the start-up time as well as protecting against the operation in the conditions of low load capacity of lubricating film, that occur during the start-on and slowing down. It allows for application of lubricant of very low viscosity and particular oil-water emulsions and water. The solution allows obtaining different, very convenient application features.

17

Tribologia obróbki skrawaniem wspomaganej ciekłym dwutlenkiem węgla ze smarem stałym

Jemielniak Krzysztof

Mechanik

|

2021

|

R. 94, nr 7

20

PL

Współczesną tendencją w obróbce skrawaniem metali jest dążenie do eliminacji szkodliwego dla środowiska chłodzenia zalewowego. Jednym ze stosowanych rozwiązań jest chłodzenie kriogeniczne ciekłym dwutlenkiem węgla (LCO2). Efektywność takiego chłodzenia można podnieść dzięki połączeniu go ze smarem stałym.

18

Optimization of tribology parameters of AZ91D magnesium alloy in dry sliding condition using response surface methodology and genetic algorithm

Beniyel M., Sivapragash M., Vettivel S. C., Senthil Kumar P., Ajith Kumar K. K., Niranjan K.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2021

|

Vol. 69, nr 1

art. no. e135835

EN

In the present research, the wear behaviour of magnesium alloy (MA) AZ91D is studied and optimized. MA AZ91D is casted using a die-casting method. The tribology experiments are tested using pin-on-disc tribometer. The input parameters are sliding velocity (1‒3 m/s), load (1‒5 kg), and distance (0.5‒1.5 km). The worn surfaces are characterized by a scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS). The response surface method (RSM) is used for modelling and optimising wear parameters. This quadratic equation and RSM-optimized parameters are used in genetic algorithm (GA). The GA is used to search for the optimum values which give the minimum wear rate and lower coefficient of friction. The developed equations are compared with the experimental values to determine the accuracy of the prediction.

19

Selected tribological parameters for silumin alloy used for engine piston

Kozuba J., Wieszała R., Mendala J., Roszak M., Pakieła W.

Archives of Materials Science and Engineering

|

2021

|

Vol. 107, nr 2

64--71

EN

Purpose: The conducted tests were aimed at determining whether the tested material meets the requirements for wear resistance in modern turbocharged combustion engines where there is an increased temperature and higher pressure. Design/methodology/approach: The tests were performed in a pin-on-disc system, according to the ASTM G 99 standard. Findings: The article presents the results of the coefficient of friction, the amount of wear, chemical analysis and surface profile of the tested material A390.0 in combination with EN GJL-350 cast iron. Research limitations/implications: The tested materials are used in the construction of pistons for internal combustion engines, therefore the test parameters were selected to take into account the operating conditions in a turbocharged engine with a power of up to 100 kW. Practical implications: After analysing the properties of the A390.0 alloy at elevated temperatures, it was found that without additional modifications, the alloy cannot be used in modern combustion engines, in particular with turbocharging. Originality/value: Presents the results of research concerning mechanical properties (HB, HV, Rm) and yield properties (R0.2, A5, Z) of the examined alloy.

20

Effect of shot peening on the surface properties, corrosion and wear performance of 17-4PH steel produced by DMLS additive manufacturing

Walczak Mariusz, Szala Mirosław

Archives of Civil and Mechanical Engineering

|

2021

|

Vol. 21, no. 4

368--387

EN

Components produced by additive manufacturing (AM) via direct metal laser sintering (DMLS) have typical as-fabricated surface defects. As a result, surface properties of AM products should be modified to increase their strength, anti-wear behaviour, and at the same time to ensure their high corrosion resistance. Surface modification via shot peening is considered suitable for additive manufacturing of medical devices made of 17-4PH stainless steel. The objective of this study was to determine the effect of shot peening pressures (0.3 MPa and 0.6 MPa) and three types of blasting media (CrNi steel shot, nutshell granules and ceramic beads) on the tribological characteristics and corrosion resistance of specimens of DMLS 17-4PH stainless steel. Results demonstrated that shot peening caused steel microstructure refinement and-except for the nutshell shot-peened specimens-induced both martensite (α) formation and retained austenite (γ) reduction. 17-4PH specimens peened with steel and ceramic shots showed the highest increase in surface hardening by approx. ~ 119% (from 247 to 542 HV), which significantly improved their wear resistance. The highest mechanical properties (hardness and wear resistance) and corrosion resistance were obtained for the surfaces modified using the following media: ceramic beads > CrNi steel shot > nutshell granules. Adhesive and fatigue wear were two predominant mechanisms of tribological deterioration. Results demonstrated that the application of shot peening using ceramic beads led to grain size refinement from 22.0 to 14.6 nm and surface roughness reduction, which in turn resulted in higher corrosion resistance of the material. DMLS 17-4PH specimens modified by shot peening using ceramic beads and a pressure of 0.6 MPa exhibited the optimum surface morphology, hardness and microstructure, and thus improved wear and corrosion performance.