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1

The influence of abrasive finishing conditions on the surface texture of Inconel 939 elements made using the 3D printing LPBF method

Wojtiuk Ewa, Radziejewska Joanna, Marczak Michał

Welding Technology Review

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2024

|

R. 96

34--40

EN

The article presents research on finishing treatment applied to components made of Inconel through 3D printing by Laser Powder Bed Fusion method. Vibration-abrasive machining was carried out using a supporting fluid and various shapes of abrasive. The effects of the processing conditions were analysed based on the surface roughness of the samples and mass loss. The obtained collective results were subjected to comparative analysis with the effects of vibratory-abrasive processing without the use of a processing fluid, as presented in the article. The research has shown that using vibration-abrasive processing, it is possible to reduce the height of surface irregularities by more than three times after four hours of treatment. The intensity of processing was the highest in the first hour of the process. The lowest roughness heights Ra = 1.8 μm were obtained using ceramic balls in the presence of a supporting fluid.

2

Influence of Surface Roughness on Tribological Properties of HS6-5-2C Steel with an AITiN Coating

Kowalczyk Joanna, Madej Monika, Kowalski Marcin

Tribologia

|

2024

|

nr 1

67--78

EN

This article defines the effect of surface roughness on a selection of tribological properties of systems with AlTiN coatings. Friction-wear tests were carried out on a tribological tester, which operates as a sphere and disc assembly in a frictional, sliding motion. The tests were conducted under a load of 10 N over a friction distance of 1,000 m. Steel discs made of HS6-5-2C with an AlTiN coating and steel balls made of 100Cr6 were used for the test Trials were carried out under lubrication conditions with polyalphaolefin oil PAO 8 and polyalphaolefin oil containing 1.5% zinc dialkyldithiophosphate (ZDDP). The chemical composition of the AlTiN coating was studied using a scanning electron microscope, and the wear marks on the discs and spheres were observed. The geometric structure of the samples was analysed before and after the geometric structure of the samples using a interferometer, and after tribological tests. Research has shown that surface roughness affects tribological properties. For samples with a higher surface roughness (Sa = 0.61 µm) – unpolished discs – lower linear wear values were obtained than for polished discs (Sa = 0.08 µm). After the introduction of the PAO 8 additive with ZDDP, a reduction in linear wear of 33% and 24% was observed for both polished and unpolished surfaces, respectively.

PL

W artykule określono wpływ chropowatości powierzchni na wybrane właściwości tribologiczne systemów z powłokami AlTiN. Badania tarciowo-zużyciowe przeprowadzono na testerze tribologicznym pracującym w skojarzeniu trącym kula–tarcza w ruchu ślizgowym. Testy wykonano przy obciążeniu 10 N na drodze tarcia równej 1000 m. Do badań użyto tarcze ze stali HS6-5-2C z naniesioną powłoką AlTiN i kule ze stali 100Cr6. Testy przeprowadzono w warunkach smarowania olejem poli(α)olefinowym PAO 8 oraz olejem poli(α)olefinowym z dodatkiem 1,5% dialkiloditiofosforanu cynku ZDDP. Za pomocą mikroskopu skaningowego zbadano skład chemiczny powłoki AlTiN, a także obserwowano ślady wytarcia na tarczach i kulach. Przy użyciu mikroskopu konfokalnego z trybem interferometrycznym dokonano analizy struktury geometrycznej próbek przed oraz po testach tribologicznych. Uzyskane wyniki badań wyskazały, że chropowatość powierzchni ma wpływ na właściwości tribologiczne. Dla próbek o większej chropowatości powierzchni (Sa = 0,61 µm) – tarcz niepolerowanych – uzyskano mniejsze wartości zużycia liniowego niż dla tarcz polerowanych (Sa = 0,08 µm). Po wprowadzeniu do PAO 8 dodatku ZDDP zaobserwowano spadek zużycia liniowego zarówno dla polerowanej i niepolerowanej powierzchni odpowiednio o 33% oraz 24%.

3

Influence of weft density on selected parameters of fabric surface

Kosiuk Gabriela, Matusiak Małgorzata

Technologia i Jakość Wyrobów

|

2023

|

R. 68

4--18

EN

The geometric structure of surface of textile materials have significant functional, operational and aesthetic importance. The basic parameters of the woven fabrics’ structure are the following: weave, warp and weft density as well as warp and weft linear density. Roughness is one of the surface quality features most often assessed by quantitative indicators called surface roughness parameters. The aim of the presented research was to analyze the parameters characterizing the geometric structure of the surface of cotton woven fabrics with twill weave. Surface topography measurements were performed using the MicroSpy® Profile profilometer by FRT the art of metrology™. The research confirmed that, on the basis of the results obtained with the profilometer, it is possible to analyze comprehensively the topography of the fabric surface.

PL

Struktura geometryczna powierzchni materiałów tekstylnych ma duże znaczenie funkcjonalne, eksploatacyjne i estetyczne. Podstawowymi parametrami struktury tkanin są: gęstość splotu, osnowy i wątku oraz gęstość liniowa osnowy i wątku. Chropowatość jest jedną z cech jakości powierzchni najczęściej ocenianych za pomocą wskaźników ilościowych, zwanych parametrami chropowatości powierzchni. Celem prezentowanych badań była analiza parametrów charakteryzujących strukturę geometryczną powierzchni tkanin bawełnianych o splocie skośnym. Pomiary topografii powierzchni przeprowadzono przy użyciu profilometru MicroSpy® Profile firmy FRT the art of metrology™. Badania potwierdziły, że na podstawie wyników uzyskanych za pomocą profilometru można kompleksowo analizować topografię powierzchni tkaniny.

4

Influence of prophylactic fluoride agents on the color changes and surface roughness of polymer and rhodium coated nickel-titanium orthodontic archwires

Alsarani Majed M., Alaida Wedad Saud, Ajwa Nancy, Alaqeel Samer M., Almutairi Naseer Meshal, Alanazi Khalid Jamal, Durgesh Pavithra, Durgesh Bangalore

Polimery

|

2023

|

Vol. 68, nr 11-12

607--616

EN

The effect of fluoride use on the color change and surface characteristics of coated nickel and titanium (NiTi) orthodontic archwires was investigated. Epoxy resin, PTFE or rhodium-coated archwires were exposed to acidulated phosphate fluoride (APF) or sodium fluoride (NaF) or artificial saliva (AS), simulating three-month clinical trials. Color changes (ΔE) were assessed using a laboratory spectrophotometer in the three-dimensional CIELab color space. The roughness (Ra) and surface structure of the archwires were examined using a non-contact profilometer and scanning electron microscopy (SEM), respectively. Data were analyzed using two-way and one-way variance (ANOVA) and post-hoc Bonferroni test (α=0.05). The average values of ΔE and Ra were the highest for epoxy-APF archwires and the lowest for rhodium-AS archwires. A significant relationship was found between the archwires surface treatment method and the ΔE and Ra values. After three months, greater changes in color and roughness were observed with APF than with AS.

PL

Zbadano wpływ stosowania fluorków na zmianę koloru i charakterystykę powierzchni powlekanych łuków ortodontycznych z niklu i tytanu (NiTi). Łuki powlekane żywicą epoksydową, PTFE lub rodem poddano działaniu zakwaszonego fluorku fosforanu (APF) lub fluorku sodu (NaF) lub sztucznej śliny (AS), symulując trzymiesięczne próby kliniczne. Zmianę koloru (ΔE) oceniano za pomocą spektrofotometru laboratoryjnego w trójwymiarowej przestrzeni kolorów CIELab. Chropowatość (Ra) i strukturę powierzchni łuków badano za pomocą odpowiednio bezkontaktowego profilometru i skaningowej mikroskopii elektronowej (SEM). Do analizy danych zastosowano dwuczynnikową i jednoczynnikową wariancję (ANOVA) oraz test Bonferroniego post-hoc (α=0,05). Wartości średnie ΔE i Ra były największe dla łuków epoksydowych-APF, a najmniejsze dla rodowych-AS. Stwierdzono istotną zależność pomiędzy metodą obróbki powierzchni łuków a wartością ΔE i Ra. Po trzech miesiącach większe zmiany koloru i chropowatości zaobserwowano w przypadku działania APF niż AS.

5

Elektrochemiczno-mechaniczne polerowanie złożonych i chropowatych części

Jemielniak Krzysztof

Mechanik

|

2023

|

R. 96, nr 1

30

PL

Opracowano nowy proces polerowania części metalowych polegający na jednoczesnym sprzężeniu wykańczania metodą przeciągania w luźnym ścierniwie (drag finishing) i polerowania elektrochemicznego. Jest on oparty na synergicznym działaniu mechanizmów ściernych i chemicznych, co umożliwia poprawę chropowatości powierzchni w ciągu kilku minut, z zachowaniem kształtu krawędzi.

6

A geometrical surface texture study of sliding sleeves and pins after bench tests

Olejarczyk Krzysztof, Wikło Marcin

Diagnostyka

|

2023

|

Vol. 24, No. 4

art. no. 2023412

EN

Objectives was to determine the durability of pins and sleeves used in the construction of a cycloidal gear. The methods used were based on a comparative analysis of selected macro photos of their surfaces and representative surface profiles recorded before and after the bench tests and the Ra and Rz surface roughness values determined on their basis. Before and after the bench tests, the weight of each sleeve and pin was measured, their surface profiles were recorded and micro photos of these surfaces were taken. Based on each recorded surface profile, the roughness parameters Ra and Rz were determined. The advantages of using steel sleeves in the cycloidal drive structure, increasing its durability, have been demonstrated by the low mass wear of the sleeves and the low surface roughness parameters Ra and Rz. It was shown that the appropriate accuracy of the pins and sleeves is necessary.

7

Effects of EDM on the Chemical Composition and Microstructure of the Surface Layer of Alnico Alloys

Bańkowski Damian, Młynarczyk Piotr, Szwed Bartłomiej

Archives of Foundry Engineering

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2023

|

Vol. 23, iss. 2

106--111

EN

This article deals with the effects of electrical discharge machining (EDM) on the chemical composition and microstructure of cast Alnico alloys, i.e., iron-based alloys composed of aluminum, nickel and cobalt. The experiments focused on determining the chemical composition of the surface layer before and after the EDM process. The microstructure of the material altered by the EDM was also examined. The study included measurement of the thickness of the white layer characteristic of EDM. It is evident that low values of the surface roughness parameters can be obtained by correctly selecting the EDM process parameters. The average surface roughness reported in the experiments was 1 μm. The surface roughness measurements were conducted with a Talysurf CCI lite non-contact profiler. The metrological results also indicate that lower surface roughness can be obtained at small discharge energies.

8

Novel drawing technology for high area reduction manufacturing of ultra-thin brass wires

Kustra Piotr, Wróbel Mirosław, Dymek Stanisław, Milenin Andrij

Archives of Civil and Mechanical Engineering

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2023

|

Vol. 23, no. 3

art. no. e144, 2023

EN

A significant increase in roughness of dieless-drawn wires due to the strain-induced roughness phenomenon has been documented. For small-diameter wires, even a slight surface relief creates stress concentrations that may contribute to the wire breakage during cold drawing. This, in turn, significantly limits the achievable diameter of the product and the efficiency of drawing process. The present study, however, demonstrates that reducing the wire roughness is possible by combining the dieless and conventional drawing methods. Thus, it is possible to improve the process workability threefold when compared to dieless drawing alone, and the product quality is simultaneously improved. In addition, the surface defects typical to the dieless-drawn wires have been significantly reduced, resulting in an increase in the wire strength. This new combined technology enables a significant reduction in the wire diameter and facilitates an economical large-scale production of ultra-thin wires. In addition, based on the classic drawing and dieless drawing process, a brass wire with a diameter of 0.017 mm has been manufactured. Six times thinner than a human hair, it is believed to be the thinnest long brass wire currently manufactured in the world.

9

Cavitation Erosion Resistance of High-Alloyed Fe-Based Weld Hardfacings Deposited Via SMAW method

Szala Mirosław, Hejwowski Tadeusz

Tribologia

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2022

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nr 4

85--94

EN

In order to investigate the cavitation erosion (CE) resistance of high-alloyed ferrous hardfacings, the three different deposits were pad welded by the shielded metal arc welding (SMAW) method. Consumable electrodes differed in the content of carbide-forming elements, and pad welds were deposited onto the S235JR structural. The CE tests, conducted according to ASTM G32 standard, indicated that hardfacings reveal lower mass loss than the reference stainless steel AISI 304 (X5CrNi18-10). The hardfacings show increasing resistance to CE in the following order: Cr-C < Cr-C-Mo < Cr-C-Mo-V-W. The reference steel revealed more than twenty times higher material loss in the CE test than Cr-C-Mo-V-W hardfacing, which had outstanding hardness (825HV0.3). The profilometric measurements and scanning electron microscopy investigations showed large changes in valley and peak sizes of the roughness profiles for materials which displayed high erosion rates. The erosion mechanism of the coatings can be classified as brittle-ductile and relies on cracking, chunk removal of material, pits and craters formation, and deformation of fractured material tips and edges. Hardfacing materials failed primarily due to brittle fractures with different severities. Specimen surface degradation follows the changes in Ra, Rz, Rv, and Rp roughness parameters and well-corresponds to the proposed roughness rate (RR) parameter.

PL

W celu zbadania odporności na erozję kawitacyjną (EK) wysokostopowych napoin na osnowie żelaza napawano trzema materiałami metodą SMAW. Elektrody otulone różniły się zawartością pierwiastków węglikotwórczych. Napoiny wykonano na stali konstrukcyjnej S235JR. Testy EK, przeprowadzone zgodnie z normą ASTM G32, wykazały niższy ubytek masy napoin w porównaniu do referencyjnej stali odpornej na korozję AISI 304 (X5CrNi18-10). Napoiny wykazują rosnącą odporność na EK w następującej kolejności: Cr-C < Cr-C-Mo < Cr-C-Mo-V-W. Referencyjna próbka stalowa wykazała w teście EK ponad dwudziestokrotnie większy ubytek materiału niż napoina Cr-C-Mo-V-W, która miała wyjątkowo wysoką twardość (825HV0.3). Pomiary profilometryczne i badania przeprowadzone przy użyciu skaningowego mikroskopu elektronowego wykazały duże zmiany wielkości dolin i szczytów profilu chropowatości dla materiałów wykazujących wysoką szybkość erozji. Mechanizm EK powłok można sklasyfikować jako krucho-plastyczny i opiera się na pękaniu, usuwaniu kawałków materiału, tworzeniu wgłębień i kraterów oraz deformacji pękniętych fragmentów kraterów oraz deformacji wyodrębnionych szczytów i krawędzi materiału. Napawany materiał podlega niszczeniu przez jego pękanie w różnym nasileniu. Degradacja powierzchni próbek pogłębia się wraz ze zmianą parametrów chropowatości Ra, Rz, Rv i Rp i dobrze koresponduje z proponowanym parametrem RR (zmiana chropowatości pow. degradowanej).

10

Badanie wpływu wybranych parametrów cyklicznego procesu mokrego trawienia chemicznego epitaksjalnych warstw InAs

Boguski Jacek, Józwowicz jakub, Nyga Małgorzta, Złotnik Sebastian, Wróbel Jarosław

Przegląd Elektrotechniczny

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2022

|

R. 98, nr 2

144--147

PL

W niniejszym artykule poświęcono uwagę procesowi mokrego trawienia chemicznego warstw epitaksjalnych InAs. Do procesu wprowadzono modyfikację, polegającą na wykonaniu trawienia w sposób cykliczny, przy założonych całkowitych czasach procesu. Zbadano wpływ ilości cykli w procesie mokrego trawienia chemicznego na głębokość trawienia oraz chropowatość strawionej warstwy.

EN

The article focuses on the wet chemical etching process of InAs epitaxial layers. A modification to the process was introduced, consisting in carrying out the etching in a cyclical manner, with the assumed total etching times. The influence of the number of cycles in the process on the etch depth and etched layer roughness was investigated.

11

Experimental studies of the possibility of laser processing as a cleaner method of achieving a surface with good adhesion

Ciecińska Barbara

Production Engineering Archives

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2022

|

Vol. 28, Iss. 3

233--240

EN

In manufacturing processes many technological operations are designed, in which the adhesive properties of the treated surface are very important. These are processes related to application of any coating on the surface, such as gluing, painting, varnishing and others. Durability of coatings depends on proper preparation of the surface to which they are going to be applied. Conventional methods, such as grinding, sandblasting with subsequent washing and degreasing, as well as galvanic treatment applied to e.g. aluminium alloys - require the use of not only specific equipment but also chemical substances. They often lead to a significant burden on the environment due to their harmful properties. In an experimental study, attention was drawn to the significant environmental aspects of such a technological process and work was carried out to demonstrate whether it is possible to eliminate toxic and hazardous substances and to create good adhesion conditions by laser processing. To this purpose, samples were made out of two representative materials: X6Cr17 steel and AW-2024 aluminium alloy, abrasive surface treatment or in a galvanic bath and then washed, degreased and dried. Laser surface treatment without the use of additional chemicals was proposed as an environmentally cleaner technology. Surface roughness and adhesion of the test polymer coating were measured for comparative evaluation of the applied treatment methods. Obtained results were discussed in terms of the possibility of eliminating harmful influences and implementing laser treatment as a cleaner technology in the production of components requiring coating.

12

Role of Si on machined surfaces of Al-based automotive alloys under varying machining parameters

Razin Ahmed Asif, Ahammed Dewan Salsabil, Nur Maglub Al, Kaiser Mohammad Salim

Journal of Mechanical and Energy Engineering

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2022

|

Vol. 6, No 1

43--52

EN

A morphological change due to Si contend into Al-based automotive alloys has been conducted on the characterization of machined surfaces in terms of roughness, temperature, chips formation as well as microstructure evaluation under different machining conditions. For this experiment, a shaper machine with HSS single point V-shaped cutting tool is used at different cutting speeds and depths of cut. The experimental results show that the surface roughness of the alloys decreases with the cutting speed and depth of cut but it is more prominent in the case of the cutting speed. This is because of a high cutting speed, which is more associated with the higher temperature and softening the work material leading to better surface finish. Higher Si added alloys also exhibit a better surface finish because the sample content is different fine and hard intermetallic due to ageing treatment, which also makes the alloys more brittle. For brittle and higher hardness, it produces a higher temperature during machining. During machining, relatively curly and short chips are formed by the high Si added alloy because of its low elongation properties. The fracture surfaces of higher Si added alloy display more crack propagation obtained by plate-like Si rich intermetallic.

13

Concrete impact strength as a measure of the resistance of a structure to external destructive energy

Fic Stanisław, Baryłka Adam, Jarosz-Hadam Monika

Inżynieria Bezpieczeństwa Obiektów Antropogenicznych

|

2022

|

Nr 3

1--9

EN

This paper presents authors’ own tests of the impact strength of concrete. The impact tests were carried out using a pendulum ballistic hammer, two types of concrete with natural aggregate: with pebble (river) gravel aggregate and medium-grained crushed granite aggregate. The concretes were tested on cubic specimens with varying W/C ratios (0.40; 0.45; 0.50; 0.55). The surface roughness of the grains in the aggregates used for the concretes was measured using a profilometer. Concrete impact strength was determined by the energy absorbed by the specimen until failure. Concrete impact strength (EA) was compared with compressive strength (fc), tensile strength (fct) and stress intensity factor (K1c).

14

Roughness effects of textured surfaces in hydrodynamic lubrication

Bahi Youssef, El Gadari Mhammed, Rahmoune Miloud

International Journal of Applied Mechanics and Engineering

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2022

|

Vol. 27, no. 3

9--21

EN

Several studies have been conducted to improve and model the lubricated contact between surfaces. The main subjects were defining the hydrodynamic parameters to reduce energy losses and protect the environment. Some of the proposed models have studied the effect of textures in hydrodynamic lubrication and have proved that adapted shapes and geometries can improve the performance of lubricated contacts. A hydrodynamic model was developed by assuming the roughness of the textured surface and considering the cavitation in a steady-state regime. The proposed model was validated and compared with the analytical model of Fowell et al. [1]. Three different textures shapes were considered. The results showed that the rough-textured thrust affects the hydrodynamic performance significantly. Thus, by increasing the arithmetic roughness of textured surfaces, the hydrodynamic pressure, and the lifting force increase depending on the texture shape. A rougher surface slightly increases the friction force for the three considered textures.

15

Key determinants for high-alloyed cast irons for mechanical engineering

Pacha-Gołębiowska H., Piekarska W.

International Journal of Applied Mechanics and Engineering

|

2022

|

Vol. 27, no. 1

146--167

EN

This work presents the factors determining cast iron, and particularly austenitic high-alloy cast iron as a construction material, which is ranked among the leading casting alloys of iron with carbon, mainly due to its very good service properties, which makes it dedicated as a material for automotive castings, pipe and fitting castings and components resistant to elevated temperatures, corrosion and abrasive wear. Construction materials currently used in industry have increasingly better properties and their potential is depleting quickly. This forces the manufacturers to adjust the requirements and production capabilities of cast iron using the most modern technologies that give the expected beneficial economic and operating effects. The paper quotes the results of research in the field of the offered technologies that give special surface features to machine parts made of cast iron by modernising the parameters of the technological process of obtaining high-alloy austenitic cast iron, i.e., by applying coatings, as well as by appropriate surface treatment, the aim of which is and reinforce the material surface with those properties which are important in a given application.

16

An approach to detect local tectonic dislocations in coal seams based on roughness analysis

Młynarczuk Mariusz, Skiba Marta

Archives of Mining Sciences

|

2022

|

Vol. 67, no. 4

743--756

EN

The occurrence of faults in coal seams has an impact on the possibility of methane hazard. There are several methods for identifying tectonic faults, but they cannot be applied directly to solve dynamic hazard problems in coal mine. Thus, searching for appropriate methods, that can detect faults in regional and local scales is needed. In order to meet this need, the paper proposes a new measurement method of estimating changes to the coal structure, based on profilometry measurements (roughness analysis) and application of madogram functions. Based on examining coal samples from near fault zones it was shown that the proposed approach allows us to detect changes of the coal surface that appear as the distance to a tectonic fault gets shorter. The proposed method, due to its simplicity and speed of measurement, implies a potential for practical application in the process of detecting local tectonic dislocations in coal mines.

17

Investigation of the workability and surface roughness of thin brass wires in various dieless drawing technologies

Milenin Andrij, Wróbel Mirosław, Kustra Piotr

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 1

art. no. e10, 2022

EN

Possibilities of improving the workability of the CuZn37 brass thin wire in a diameter of 0.14–0.18 mm produced by the dieless drawing processes were explored. The workability was defined as the maximum final longitudinal strain of the wire up to its fracture, achievable in the dieless drawing process. Two technologies of dieless drawing were developed and their workability was compared. The first one is the classical one-pass process; the second, a multi-pass one. For both developed technologies, it was possible to obtain a good-quality product but more than two times higher workability has been demonstrated for the multi-pass technology. No evident effect of the deformation temperature from the window of technologically accepted parameters on the workability was found but an increase in the temperature significantly increased the roughness of the product surface. For the same deformation temperature, the roughness of the wire obtained from the multi-pass process appeared to be significantly lower than for the one of the classical one-pass technologies.

18

Cavitation erosion phenomenological model of MCrAlY and NiCrMoNbTa metallic coatings deposited via the HVOF method

Szala Mirosław

Tribologia

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2021

|

nr 4

45--55

EN

The work describes the phenomenological model of cavitation erosion (CE) elaborated for MCrAlY (where M = Co, Ni or Co/Ni) and NiCrMoNbTa. Coatings were deposited via the HVOF method from CoNiCrAlY, NiCoCrAlY and NiCrMoNbTa feedstock powders. CE tests, conducted according to ASTM G32 standard, indicate that MCrAlYs have a 50% higher maximum erosion rate and twice lower CE resistance than the NiCrMoNbTa coating. CE kinetics of coatings were comparatively studied, combining the mass loss, erosion rate, roughness changes of the eroded surface with microstructure, and mechanical properties of the coatings. Results of SEM analysis of damaged coatings allow identifying the mechanism of CE. In the case of both types of coatings, the erosive damage is initiated at the removal of loose splats, cracking at the border splats and peeling off the coating material, and surface pitting. However, NiCrMoNbTa, due to higher ductility and microstructure homogeneity, presents lesser surface pitting contrary to the MCrAlYs, which have multiphase microstructure higher hardness and consequently was prone to cracking, resulting in the formation of craters and higher surface roughening. The CE mechanism of MCrAlYs was dominated by the brittle mode, while the NiCrMoNbTa coating has mainly a ductile damage behaviour.

PL

W pracy opisano fenomenologiczny model erozji kawitacyjnej (EK) opracowany dla powłok MCrAlY (gdzie M = Co, Ni lub Co/Ni) i NiCrMoNbTa. Powłoki wytworzono metodą HVOF z komercyjnych proszków CoNiCrAlY, NiCoCrAlY i NiCrMoNbTa. Testy erozji kawitacyjnej, przeprowadzone zgodnie z normą ASTM G32, wskazują, że MCrAlY mają o 50% wyższą prędkość erozji i dwukrotnie niższą odporność EK niż powłoka NiCrMoNbTa. Kinetyka erozji kawitacyjnej powłok została poddana analizie porównawczej syntetyzującej utratę masy, szybkość erozji, zmiany chropowatości erodowanej powierzchni z mikrostrukturą oraz właściwościami mechanicznymi badanych powłok. Wyniki analizy SEM uszkodzonych powłok umożliwiły zidentyfikowanie mechanizmu EK. Uszkodzenie erozyjne powłok inicjowane jest w wyniku usuwaniu słabo umocowany cząstek materiału, pękaniu na granicach lameli następnie usuwaniu materiału i tworzeniu wżerów. Jednak NiCrMoNbTa ze względu na wyższą ciągliwość i jednorodność mikrostruktury wykazuje mniejsze wżery powierzchniowe w przeciwieństwie do MCrAlYs, które cechują się wielofazową mikrostruktura o wyższej twardości i w konsekwencji są podatne na pękanie, co powoduje powstawanie dużych wżerów i wyższe chropowacenie powierzchni. Mechanizm erozji kawitacyjnej powłok MCrAlY jest zdominowana przez kruche pękanie, natomiast w przypadku powłoki NiCrMoNbTa dominuje plastyczne odkształcenie.

19

Numerical simulation of flow through microchannels of technical equipment with triangular and rectangular elements of roughness

Kmiotek Małgorzata, Iwan Tomasz

Technologia i Automatyzacja Montażu

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2021

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nr 4

16--23

PL

Celem pracy jest określenie wpływu chropowatej powierzchni na przepływ płynu w mikrokanałach stosowanych w różnych mikrourządzeniach technicznych złożonych wyrobów. Rozpatrywano dwuwymiarowy osiowo-symetryczne mikrokanały o przekroju kołowym. Chropowatość została zasymulowana jako proste figury geometryczne tj. trójkąt i prostokąt o różnej wysokości h i różnej odległości s między sobą. Równania przepływowe zostały rozwiązane za pomocą oprogramowania Ansys/Fluent. Przeprowadzana jest analiza linii prądu w celu zbadania przepływów w strefie recyrkulacji za elementami chropowatości. Stwierdzono, że współczynnik tarcia wzrasta wraz ze wzrostem wysokości elementów chropowatych. Współczynnik tarcia jest większy dla elementów prostokątnych niż trójkątnych i zmniejsza się wraz ze zmianą geometrii elementu. Straty tarcia maleją wraz ze wzrostem liczby Reynoldsa. Autorzy wskazują, że w produkcji mikrokanałów złożonych wyrobów do modelowania chropowatości zaleca się używać elementów trójkątnych.

EN

This paper presents a computational study on an influence of a rough surface on the fluid flow in a microchannel used in various technical microdevices of complex products. Two-dimensional axially symmetrical microchannels with a circular cross-section were considered. The fluid flow were simulated as simple geometric figures, i.e. a triangle and a rectangle with different height h and different distance s between each other. The flow equations were solved with Ansys / Fluent software. A streamline analysis is performed to investigate the flows in the recirculation zone behind the roughness elements. It was found that the friction factor increases with increasing height of rough elements. The coefficient of friction factor is greater for rectangular elements than for triangular elements, and decreases as the geometry of the element changes. Friction factor decreases as the Reynolds number increases. The authors indicate that in the production of microchannels of complex products, it is recommended to use triangular elements to model roughness.

20

Experimental study of mild steel cutting process by using the plasma arc method

Magid H.M.

Journal of Achievements in Materials and Manufacturing Engineering

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2021

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Vol. 108, nr 2

75--85

EN

Purpose: In this study, plasma arc cutting (PAC) is an industrial process widely used for cutting various away types of metals in several operating conditions. Design/methodology/approach: It is carried out a systematic or an authoritative inquiry to discover and examine the fact, the plasma cutting process is to establish the accuracy and the quality of the cut in this current paper assessed a good away to better the cutting process. Findings: It found that the effect of parameters on the cutting quality than on the results performed to accomplish by statistical analysis. Research limitations/implications: The objective of the present work paper is to achieve cutting parameters, thus the quality of the cutting process depends upon the plasma gas pressure, scanning speed, cutting power, and cutting height. Practical implications: The product of the plasma cutting process experimentally has been the quality of the cutting equipment that was installed to monitor kerf width quality by exam the edge roughness, kerf width, and the size of the heat-affected zone (HAZ). Originality/value: The results reveal that were technically possessed of including all the relevant characteristics, then a quality control for the cutting and describe the consequence of the process parameters.