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1

The influence of carbide reinforcement on the properties of sintered aluminium alloy matrix composites

Szewczyk-Nykiel Aneta

Technical Transactions

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2023

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Vol. 120, iss. 1

art. no. e2023005

EN

Based on the commercial aluminium alloy powder blend (Alumix 431D) metal matrix composites reinforced with particles of SiC as well as TiC were produced by conventional powder metallurgy technology and the effect of the type and amounts of reinforced particles on the selected properties and microstructure of sintered composites were investigated. In particular, the densification behaviour, the wear resistance and the corrosion resistance in 3.5% NaCl solution were identified. It was stated that both the type and the weight fraction of carbide used as particulate reinforcement have a great impact on the properties of aluminium alloy matrix composites. It was shown that the introduction of titanium carbide has a more favourable effect on the properties of sintered Alumix 431D matrix composites in comparison to silicon carbide and the optimum content of TiC in composite is 4 wt. % due to the highest hardness, wear resistance (wear rate of 2.865·10 ̄ ³ mm³/m) and simultaneously the best corrosion resistance (corrosion rate of 0.005 mm/year).

2

Powłoki natryskiwane plazmowo dla potrzeb przemysłu chemicznego

Morel Sławomir

Przemysł Chemiczny

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2023

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T. 102, nr 4

355--361

PL

Opisano przeznaczenie i zakres zastosowań powłok natryskiwanych cieplnie. Scharakteryzowano plazmę stosowaną do natryskiwania powłok. Dokonano ogólnej charakterystyki najczęściej stosowanych materiałów powłokowych i wyszczególniono ważniejsze właściwości powłok decydujące o ich przydatności dla potrzeb przemysłu i gospodarki. Przytoczono ważniejsze przykłady eksploatacji urządzeń pracujących z natryskanymi powłokami, zamieszczając osiągnięte efekty oddziaływania powłok na wzrost trwałości i efektywności pracy cieplnej.

EN

A review, with 14 refs, of the range of applications of thermal sprayed coatings using plasma. The plasma used for spraying coatings was characterized. The general characteristics of the most commonly used coating materials were presented, and the most important coating properties detg. their suitability for industrial applications were indicated. Examples of the operation of devices working with sprayed coatings were given, including the effects of coatings on increasing the durability and efficiency of thermal operation.

3

The Influence of Pearlite Present in the Microstructure of GX120MnCr13 Cast Steel on Wear Resistance

Kalandyk Barbara, Zapała Renata, Sulima Iwona, Furmańczyk Piotr, Kasińska Justyna

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

145--156

EN

The article presents the results of metallographic and tribological tests on GX120MnCr13 cast steel that was previously subjected to heat treatment (including solution treatment from 1100°C and isothermal holding at 250, 400, and 600°C for 100 hours). The temperatures of the isothermal holding process were selected in order to reflect the possible working conditions of the cast elements that can be made of this cast steel. Wear tests were carried out under dry friction conditions using the ball-on-disc method using a ZrO2 ball as a counter-sample. The tests were carried out with a load of 5 N. The influence of the long-term isothermal holding process on the microstructure of the tested cast steel was analysed by light and scanning microscopy; however, abrasion marks were also examined using a confocal microscope. Based on the tests conducted, it was found that in the microstructures of the sample after solution treatment and samples that were held in isothermal C, the grain boundary areas were enriched in Mn and Cr compared to the areas inside the grains. Pearlite appearedcondition at 250 and 400 in the sample that was heated (or held in isothermal holding) at 600°C; its share reached 41.6%. The presence of pearlite in the austenitic matrix increased the hardness to 351.4 HV10. The hardness of the remaining tested samples was within a range of 221.8-229.1 HV10. Increasing the hardness of the tested cast steel directly resulted in a reduction in the degree of wear as well as the volume, area, and width of the abrasion marks. A microscopic analysis of the wear marks showed that the dominant process of the abrasive wear of the tested friction pair was the detachment and displacement of the tested material through the indentation as a result of the cyclical impact of the counter sample.

4

Hob wear prediction based on simulation of friction, heat fluxes, and cutting temperature

Hrytsay Ihor, Stupnytskyy Vadym

Archive of Mechanical Engineering

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2023

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LXX, nr 2

271--286

EN

Based on comprehensive interrelated mathematical and graphical-analytical models, including 3D cut layers and simulation of contact, strain, force, and thermal processes during gear hobbing friction forces, heat fluxes, and temperature on the teeth of the hob surface are investigated. Various physical phenomena are responsible for their wear: friction on contact surfaces and thermal flow. These factors act independently of each other; therefore, the worn areas are localized in different active parts of the hob. Friction causes abrasive wear and heat fluxes result in heat softening of the tool. Intense heat fluxes due to significant friction, acting on areas of limited area, lead to temperatures exceeding the critical temperature on certain edges of the high-speed cutter. Simulation results enable identification of high-temperature areas on the working surface of cutting edges, where wear is caused by various reasons, and make it possible to select different methods of hardening these surfaces. To create protective coatings with maximum heat resistance, it is advisable to use laser technologies, electro spark alloying, or plasma spraying, and for coatings that provide reduction of friction on the surfaces – formation of diamond-containing layers with minimum adhesion properties and low friction coefficient on the corresponding surfaces.

5

Influence of Pre-Hardened Gx120mn13 Cast Steel on the Tribological Properties under Technically Dry Friction

Kalandyk Barbara, Zapała Renata, Madej Monika, Kasińska Justyna, Piotrowska Katarzyna

Tribologia

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2022

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nr 3

17--24

EN

This paper presents the results of tribological tests on high manganese GX120Mn13 cast steel under technically dry friction conditions. The tests were carried out using a TRB3 ball-on-disc tribometer using a 6mm-diameter SiC ball as a counter-sample for a specimen made of GX120Mn13 cast steel containing a localised prehardening area on the test surface with a hardness of approximately 597 HV10 (the non-hardened area had a hardness of approximately 325–364 HV10). During the test, the ball travelled in a 16.68 mm diameter circle and passed through both hardening and non-hardened areas. The resulting erosion marks were assessed using an optical profilometer and scanning microscope tests, which showed that the maximum depth of erosion in the previously hardening area was 0.77 µm and was more than twice as deep as in the non-hardened areas surveyed. In contrast, the area of attrition was twice as small as in the non-hardened area located in the axis of the previously applied load and more than three times smaller, but in the area located on the side of the axis and 8.34 mm away from it. Thus, from the point of view of the abrasion resistance of GX120Mn13 cast steel, the validity of its prior hardening before the operation was confirmed.

PL

W artykule przedstawiono wyniki badań tribologicznych wysokomanganowego staliwa GX120Mn13 w warunkach tarcia technicznie suchego. Badania przeprowadzono przy użyciu tribometru TRB3 typu ball–on– disc stosując jako przeciwpróbkę kulkę z SiC o średnicy 6mm dla próbki wykonanej ze staliwa GX120Mn13 zawierającej na powierzchni badanej lokalny obszar wcześniej umocniony o twardości ok. 597 HV10 (obszar nieumocniony posiadał twardość ok 325–364 HV10). Kulka w czasie testu poruszała się po okręgu o średnicy 16.68 mm i przechodziła zarówno przez obszar umocniony, jak i nieumocniony. Otrzymane ślady wytarcia oceniano za pomocą badań wykonanych na profilometrze optycznym i mikroskopie skaningowym. Na podstawie przeprowadzonych badań wykazano, że w obszarze wcześniej umocnionym maksymalna głębokość wytarcia wynosiła 0.77 µm i była ponad dwukrotnie mniejsza niż w badanych obszarach nieumocnionych. Z kolei pole wytarcia było dwukrotnie mniejsze niż w obszarze nieumocnionym, znajdującym się w osi przyłożonego wcześniej obciążenia i ponad trzykrotnie mniejsze w porównaniu z obszarem znajdującym się z boku osi i oddalonym od niej o 8.34 mm. Tym samym, z punktu widzenia odporności na zużycie ścierne staliwa GX120Mn13, potwierdzono słuszność jego wcześniejszego umocnienia przed eksploatacją.

6

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

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2022

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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.

7

Effect of friction surfacing parameters on the microstructural, mechanical properties, and wear characteristic of Al‑Cu‑Mg alloy coating reinforced by nickel aluminide

Farajollahi Ramezanali, Aval Hamed Jamshidi, Jamaati Roohollah

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e75, 1--18

EN

This research has studied the microstructure, mechanical properties, and tribological properties of AA2024-Al3NiCu composite coating fabricated by friction surfacing. The Al3NiCu intermetallic was created in the aluminum matrix by adding nickel during the stir casting process and then performing the homogenization treatment. The results showed that with increasing the axial feeding rate from 87.5 to 125 mm/min and the rotational speed from 600 to 800 rpm, the coating efficiency grew up to 79%. Moreover, no significant microstructural differences (grain size, precipitate size, and morphology) were observed in different parts of the coating. Applying the coating at a rotational speed of 800 rpm, a traverse speed of 125 mm/min, and an axial feeding rate of 125 mm/min raised the hardness and shear strength of the AA2024 aluminum alloy substrate by 17% and 21%, respectively, while lowering its wear rate by 37%.

8

A geometrical surface texture study of cycloid drive discs after bench tests

Olejarczyk Krzysztof, Kalbarczyk Marek

Tribologia

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2021

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nr 3

27--33

EN

The article presents the results of a geometrical surface texture study of cycloid drive discs after bench tests. For this purpose, the working surfaces, such as peak and valley areas of the epicycloid and the holes inner surfaces of both discs, were investigated using contact profilometry. From each surface, a transverse profiles were extracted, before and after 50 cycles of bench test. The discs and the profiles were examined for signs of wear and roughness changes. For each profile, the Ra and Rz roughness parameters were determined. On the base of the obtained profiles and the values of roughness parameters, it can be stated that the assumed test parameters provide stable working conditions, with an uninterrupted lubrication film, which results in practically negligible and unmeasurable wear. Taking into account the operating specification of a helicopter winch as an example of potential application of the presented cycloidal drive, the developed solution fulfils the requirements concerning wear resistance

PL

W artykule zaprezentowano wyniki badań laboratoryjnych trwałości kół przekładni cykloidalnej. W tym celu z powierzchni współpracy kół wyodrębniono obszary szczytu i doliny powierzchni epicykloidalnej, a także wewnętrzne powierzchnie otworów, które poddano badaniom przy użyciu profilometrii stykowej. Dla każdej z powierzchni wyznaczono profile chropowatości przed i po 50 cyklach testu stanowiskowego. Koła, jak również profile zostały poddane analizie pod kątem obecności śladów zużycia i zmian chropowatości. Dla każdego z uzyskanych profili wyznaczono parametry chropowatości Ra i Rz. W oparciu o uzyskane profile i wartości parametrów chropowatości można stwierdzić, że przyjęte parametry testowe zapewniają stabilne warunki pracy z nieprzerwanym filmem smarowym, czego efektem jest niemalże pomijalne, niemierzalne zużycie. Jednym z przykładowych zastosowań opracowanej przekładni cykloidalnej jest wyciągarka śmigłowcowa, a biorąc pod uwagę specyfikę jej pracy, uzyskane rozwiązanie konstrukcyjne spełnia wymagania dotyczące zapewnienia wystarczającej odporności na zużycie.

9

A Discussion on the Physical Interpretation of Measurements of Tribological Wear

Sadowski Jan

Tribologia

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2021

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nr 1

27--37

EN

Physical sense and practical significance of major measurements of tribological wear are analysed here. Definitions and methods of assessing these measurements are proposed on the basis of the laws of energy and mass conservation. Contributions of energy and displacement of particular friction forces corresponding to each element of a friction couple are addressed. Energy expenditure that causes wear is introduced into the definition of wear resistance. Planning and thermodynamic analysis of a tribological experiment and the application of thermodynamic concepts and quantities to the description and the interpretation of results are recommended. The author believes application of wear measures that have an unequivocal physical interpretation will limit problems with the incomparability and the irreproducibility of tribological results and issues with transferring them to real objects.

PL

W niniejszej pracy zanalizowano senes fizyczny i praktyczne znaczenie ważniejszych miar zużycia tribologicznego. Zaproponowano definicje i sposoby oceny tych miar w oparciu o zasady zachowania energii i masy. Uwzględniono w nich udział energii i przemieszczenia poszczególnych sił tarcia, które przypadają na każdy z elementów pary ciernej. Do definicji odporności na zużycie wprowadzono nakład energii, który je spowodował. Zalecono zaplanowanie eksperymentu tribologicznego z jego analizą termodynamiczną oraz wykorzystanie pojęć i wielkości termodynamicznych do opisu i interpretacji uzyskanych wyników. Zdaniem autora stosowanie miar zużycia mających jednoznaczną interpretację fizyczną ograniczy problemy nieporównywalności i nie odtwarzalności wyników badań tribologicznych oraz trudności ich przenoszenia na obiekty rzeczywiste.

10

Odporność na zużycie zewnętrznych syntetycznych nawierzchni sportowych

Strąk Cezary, Sudoł Ewa

Materiały Budowlane

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2021

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nr 10

28--30

PL

Celem pracy było ustalenie odporności na zużycie syntetycznych nawierzchni sportowych w obiektach zewnętrznych. Przeprowadzono badania ścieralności trzech rodzajów nawierzchni – typu natrysk (SP), pełny EPDM oraz dwuwarstwowej (2S). Określono ubytek masy zarówno próbek sezonowanych w warunkach laboratoryjnych, jak i poddanych sztucznemu starzeniu polegającemu na działaniu wysokiej temperatury, w tym w środowisku wody, oraz cyklom zamrażania-rozmrażania. Wszystkie testowane rozwiązania wykazały dużą odporność na zużycie, przy czym najmniejszy ubytek masy odnotowano w przypadku nawierzchni typu SP. Nie zaobserwowano istotnego wpływu zadanych oddziaływań na rozpatrywaną właściwość.

EN

The aim of the study was to determine the wear resistance of synthetic sports surfaces for outdoor areas. The abrasion resistance tests of three types of surface were carried out – spray type (SP), full EPDM and two-layer (2S). The weight loss was determined for both samples seasoned in laboratory conditions and those subjected to artificial aging involving the action of high temperature, including in the water environment and freeze-thaw cycles. All tested solutions showed high resistance to wear, with the smallest weight loss recorded for the SP surface. No significant influence of the given exposures on the considered property was observed.

11

Influence of orientation of zones of higher hardness of composite layers on their resistance to wear

Peremitko V.V., Kolomoyets I.V.

Archives of Materials Science and Engineering

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2021

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Vol. 110, nr 2

59--71

EN

Purpose: Experimentally substantiate the influence of the orientation of zones of higher hardness on the wear mechanism of contact surfaces. Design/methodology/approach: Forming of variable composition within the working surfaces of parts is a common way to solve the problem of uneven wear. The tests were aimed at determining the characteristics of the layers surfaced with the orientation of the zones of high hardness. For this different tests and measurements were done. Before the test, samples of 45 steel were surfaced with a preliminary application of titanium carbide paste. Findings: As a result of researches it was found that different ways of the orientation of zones of higher hardness have different influences on the characteristics of a surface. The main conclusion is that the transverse orientation of such zones helps to increase the wear resistance of the surface and to save its original relief. Research limitations/implications: The roughness, wear resistance, zonal hardness, and relief of layers surfaced with the orientation of zones of higher hardness were studied. Practical implications: The results obtained are useful in the field of rolling production and mechanical engineering to avoid the uneven wear of parts and as a result to extend the term of their exploitation. Originality/value: In this paper the model concepts of wear process of surfaces with variable composition and measurements of characteristics of surface considering its local hardening are proposed.

12

Effect of milling time on microstructure of cobalt ferrites synthesized by mechanical alloying

Tomiczek Anna E.

Archives of Materials Science and Engineering

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2021

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Vol. 111, nr 1

5--13

EN

Purpose: of this paper is to determine the effect of manufacturing conditions, especially milling time, on the microstructure and phase composition of CoFe2O4 cobalt ferrite. Design/methodology/approach: Cobalt ferrite (CoFe2O4) has been synthesised from a stoichiometric mixture of CoCo3 and α-Fe2O3 powders in a high energy planetary mill. Annealing at 1000°C for 6 hours after milling was used to improve the solid-state reaction. Calcinated samples were analysed by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The relationship between the milling time of powders, their microstructure, as well as their properties were evaluated. Particles size distribution and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) examination were also made. Findings: CoFe2O4 ferrites were successfully synthesized by mechanical alloying of α-Fe2O3 and CoCO3 powders. The powder particles had undergone morphological changes with the increasing milling time. However, the milling time does not affect the ferrite formation rate. It is expected that the improvement of fabrication parameters can further enhance the properties of cobalt ferrite presented in this work. Research limitations/implications: Contribute to research on the structure and properties of cobalt ferrites manufactured by mechanical alloying. Practical implications: The reactive milling and subsequently annealing is an efficient route to synthesise cobalt ferrite powder. However, using steel milling equipment risks powder contamination with iron and chromium from the vials and balls. Originality/value: The results of the experimental research of the developed ferrite materials served as the basis for determining material properties and for further investigation.

13

Evaluation of Microstructure and Tribological Properties of GX120Mn13 and GX120MnCr18-2 Cast Steels

Kalandyk B., Zapała R., Kasińska J., Madej M.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 4

77--81

EN

The results of microstructure examinations and hardness measurements carried out on two selected grades of high-manganese cast steel with an austenitic matrix, i.e. GX120Mn13 and GX120MnCr18-2, are presented. The examinations of the cast steel microstructure have revealed that the matrix of the GX120MnCr18-2 cast steel contains the precipitates of complex carbides enriched in Cr and Mn with two different morphologies. The presence of these precipitates leads to an increase in hardness by approx. 30 HB compared to the GX120Mn13 cast steel. Samples cut out from the tested materials were loaded (10 strokes) with an energy of 53 J, and then a ball-on-disc tribological test was performed. The test was carried out in reciprocating motion under technically dry friction conditions. While analyzing the obtained results of the microstructure, hardness, and abrasion tests, it was found that the presence of the hard carbide precipitates in the plastic matrix of the tested GX120MnCr18-2 cast steel promoted an increase in hardness, but also led to chipping of these particles from the alloy matrix, thus contributing to micro-cutting during friction.

14

Effect of SiZr Modification on the Microstructure and Properties of High Manganese Cast Steel

Sobula S.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 4

82--86

EN

The paper presents the results of research on GX120Mn13 modification performed with the SiZr38 inoculant. The microstructure of Hadfield cast steel in as-cast condition was studied through optical microscopy before and after inoculant introduction into the liquid steel. After heat treatment, mechanical properties and wear resistance tests were conducted to analyse the influence of the inoculant. The wear rate was determined according to the Standard Test Method for Determination of Slurry Abrasivity (ASTM G-75). The results show that average grain diameter, area of eqiuaxed grains crystallization and secondary dendrite arm spacing were lower after inoculation. After inoculation, the ultimate tensile strength and proof strength were higher by 8% and 4% respectively, in comparison to the initial state. The results of abrasion wear tests show that the introduction of 0.02 wt. % of zirconium significantly improved wear resistance, which was 34% better in comparison to steel without zirconium.

15

Influence of gradient structure on wear characteristics of centrifugally cast functionally graded magnesium matrix composites for automotive applications

Saleh Bassiouny, Jiang Jinghua, Fathi Reham, Xu Qiong, Li Yuhua, Ma Aibin

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

196--218

EN

In the past few years, the functionally graded materials (FGMs) have proved useful in many industrial applications such as aerospace, automotive, transportation and infrastructure because of their advantages like the ability to control mechanical properties, residual stresses, wear, and corrosion behavior through a smooth gradation of the elements in a particular direction of the products. In this current work, the microstructural and wear properties of AZ91 alloy reinforced with silicon carbide particles (SiCp) produced through the centrifugal casting method were investigated. Four weight fractions of SiCp with 10 µm average size were used to fabricate functionally graded (FG) tubes in the two mold rotational speeds of 1200 and 1500 rpm. Microstructural, microhardness, and wear tests were used for characterizing the developed FG tubes. From the results obtained, the gradient distribution of SiC particles inside the AZ91 matrix alloy substantially improved hardness and wear resistance for the FG tubes comparing to unreinforced alloy. Moreover, the mold rotational speed is the main factor in controlling the distribution of particles, thus determining the gradient properties of the manufactured FG tubes. These findings suggest that FG tubes are useful for aerospace and automotive applications that require more excellent surface resistance.

16

Simulation of loading and wear rate distribution on cutting edges during gears hobbing

Hrytsay Ihor, Stupnytskyy Vadym, Topchii Vladyslav

Archive of Mechanical Engineering

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2021

|

LXVIII, nr 1

51--76

EN

Results of complex mathematical and computer simulation of gear hobbing are given. A systematic approach to research allowed for the development of simulation models and sequencing of all aspects of this complex process. Based on the modeling of non-deformable chips, a new analytical method for analyzing hobbing has been proposed. The shear, friction and cutting forces at the level of certain teeth and edges in the active space of the cutter are analyzed depending on the cut thickness, cross-sectional area, intensity of plastic deformation and length of contact with the workpiece has been developed. The results of computer simulations made it possible to evaluate the load distribution along the cutting edge and to predict the wear resistance and durability of the hob cutter, as well as to develop measures and recommendations for both the tool design and the technology of hobbing in general. Changing the shape of cutting surface, or the design of the tooth, can facilitate separation of the cutting process between the head and leading and trailing edges. In this way, more efficient hobbing conditions can be achieved and the life of the hob can be extended.

17

Hardfacing of metal-cutting tools by arc welding in vacuum

Ferdinandov N. V., Gospodinov D. D.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 99, nr 2

49--56

EN

Purpose: To present a technology for hardfacing of metal-cutting tools by arc welding in vacuum. Design/methodology/approach: The experiments were carried out using an installation for arc welding in vacuum. Objects of research were metal cutting tools (lathe knives), made of high-speed steel HS6-5-2 on a base metal of structural steel C45. The structure, hardness and wear resistance after hardfacing and after a triple tempering at 560°C have been determined. The heat resistance of the obtained instruments has been examined. Findings: The microstructural analysis showed that the structure of the built-up layer consisted of martensite, retained austenite and carbides. This was confirmed by the values of measured hardness after welding which were about 63-64 HRC. The triple tempering led to an increase in hardness by 3-4 HRC. It was found that the built-up layers (cutting edges of tools) retain their hardness (HRC=63-65) up to a temperature of 615-620°C, which shows that the heat resistance of the build-up layers was similar to that of the hardened and tempered tools of the same steel. The built-up work-pieces (excluding heat treated) and the reference knife showed the same cutting qualities at cutting speeds in the range of 55 to 120 m/min. It has been found that triple tempering after hardfacing led to increased wear resistance and consequently the durability of the tool also increased due to the higher hardness. Practical implications: The practical application is related to the production of metalcutting tools. Originality/value: The proposed technological method allows to produce defects free built-up layers. The cutting properties of the built-up in vacuum layers are comparable to or better than those of new tools made of steel HS 6-5-2.

18

Badania odporności na zużycie ścierne kompozytowych powłok (stop kobalt-WC) wytworzonych metodą LENS

Klimek Joanna, Dworecka-Wójcik Julita, Durejko Tomasz, Zasada Dariusz

Inżynieria Powierzchni

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2020

|

nr 1-2

38--47

PL

Powłoki metaliczne umacniane fazą wzmacniającą należą do szeroko stosowanych materiałów odpornych na zużycie. W pracy podjęto próbę wytworzenia powłok kompozytowych w układzie osnowa metaliczna (stop kobaltu) – faza wzmacniająca (węglik wolframu) stosując w tym celu technikę Laser Engineered Net Shaping (LENS). Otrzymane powłoki poddano ocenie jakości metalurgicznej (poprzez obserwacje mikroskopowe), badaniom mikrotwardości w strefie przejściowej powłoka-podłoże oraz badaniom odporności na zużycie ścierne w warunkach tarcia suchego. W tym celu wykorzystano dwie różne techniki badawcze: metodę kula-tarcza oraz badania odporności w luźnym ścierniwie. W przypadku każdej z metod zastosowano tę samą siłę docisku oraz liczbę obrotów tarczy/rolki. Przeprowadzone badania wykazały, że ubytek masy powłok poddanych badaniom odporności na zużycie w luźnym ścierniwie był znacznie większy w odniesieniu do metody kula-tarcza.

EN

Metallic coatings strengthened by the reinforcing phase are among the widely used wear-resistant materials. The work attempted to produce composite coatings in the metallic matrix system (cobalt alloy) – reinforcing phase (tungsten carbide) fabricated by the Laser Engineered Net Shaping (LENS) technique. The obtained coatings were assessed by metallurgical quality (microscopic observations), microhardness test in coating-substrate transition zone and tests of abrasive wear resistance under dry friction conditions. For this purpose, two different test methods were used: the ball-on-disc method and the rubber wheel abrasion test method. For each method, the same test parameters were used, such as force and number of disc/ roller rotations. The conducted tests showed that the weight loss of the coatings subjected to wear resistance tests in loose abrasive was much greater compared to the ball-on-disc method.

19

Fly ash/phenolic resin composite for brake pad application : fabrication, materials and thermal properties

Savetlana Shirley, Lubis Asnawi, Aditya Lingga, Irfan Muhammad, Siadari Dedi, Efendi Gunawan, Yusuf Muhammad, Jefri Hel

Composites Theory and Practice

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2020

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R. 20, nr 3-4

95--101

EN

Nowadays, many parts of automotive components are made of composites. One application of composites is brake lining material in braking systems. Fly ash is waste from burning coal in the power plant industry. Fly ash was added to a polimer matrix to enhance the wear properties of the composite. The appropriate temperature and pressure for composite fabrication were chosen from the composite which has the highest hardness. The addition of 30 wt.% fly ash to the phenolic resin matrix resulted in the lowest specific abrasion of the composite. Additions of graphite, iron powder and nitrile butadiene rubber increased the specific abrasion of the fly ash/phenolic resin composite. Scanning electron microscope micrographs showed the distribution and agglomeration of the particles in the phenolic resin matrix. The addition of fly ash to the phenolic resin matrix also increased the temperature resistance of the composite. Thermogravimetric analysis shows that the starting temperatures for decomposition of the composite constituents shifted to higher temperatures as the fly ash content increases.

20

Solid Particle Erosion of Laser Surface Melted Ductile Cast Iron

Kotarska A., Janicki D., Górka J., Poloczek T.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

105--111

EN

The article presents research on solid particle erosive wear resistance of ductile cast iron after laser surface melting. This surface treatment technology enables improvement of wear resistance of ductile cast iron surface. For the test ductile cast iron EN GJS-350-22 surface was processed by high power diode laser HPDL Rofin Sinar DL020. For the research single pass and multi pass laser melted surface layers were made. The macrostructure and microstructure of multi pass surface layers were analysed. The Vickers microhardness tests were proceeded for single pass and multi pass surface layers. The solid particle erosive test according to standard ASTM G76 – 04 with 30°, 60° and 90° impact angle was made for each multi pass surface layer. As a reference material in erosive test, base material EN GJS-350-22 was used. After the erosive test, worn surfaces observations were carried out on the Scanning Electron Microscope. Laser surface melting process of tested ductile cast iron resulted in maximum 3.7 times hardness increase caused by microstructure change. This caused the increase of erosive resistance in comparison to the base material.