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1

A Comparative Study of Tribological Behavior of Moglice and DK-6(PT) Composites

Pashechko Mykhailo, Ishchenko Аnatoliy, Radionenko Aleksandr, Kindrachuk Myroslav, Tisov Oleksandr

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 1

149--157

EN

Authors have produced new polymer-based composite material DK-6(PT) for substitution of Moglice (Diamant) polymer. We manufactured and used sliding-friction test apparatus (pin-on-disc) capable of testing three specimens simultaneously, much reducing time for the test. The monitoring of the material curing process and the Shore hardness test indicate minor difference from reference material. Measurements were carried out during the curing period, since it is important to know change in this parameter over time. The wear test proved that DK-6(PT) composite in the long-time test has good wear resistance: over 80 km of the friction path, the wear loss of both materials is approximately the same. Furthermore, the friction factor of DK-6(PT) is 5–10% less than that of Moglice. Thus, the studied new polymeric composite may compete with well-known material Moglice and significantly cut the expenses for reconditioning of worn slide ways of metal working equipment.

2

Combined method for surface hardening of Р6M5 steel by deposition of N + Ti and N + Cr diffusion coatings and selective laser post-treatment of substrate

Pashechko Mykhaylo, Kindrachuk Myroslav, Khyzhnyak Viktor, Tisov Oleksandr, Zagrebelniy Volodymyr, Yurchuk Alina

Inżynieria Materiałowa

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2019

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Vol. 40, nr 1

9--13

EN

The main aim of current research is to improve wear resistance of tool steels. Chemical heat treatment is a well-known method to do this. Nitriding is a well known method of improving surface hardness and wear resistance. Due to high hardness, low thickness, these coatings often crack and spall out of the substrate. We supposed that varying hardness and composition of the coating will facilitate wear resistance and will help to avoid coating cracking. In this order we propose to use selective laser treatment of cutting edge by laser beam after chemical heat treatment. This locally changes the structure of steel, thus changing the thickness and hardness of coating. A following chemical heat treatment was done — single- (nitriding with laser pre-treatment) and bilayer (nitriding + metallization with laser post-treatment) coatings. Laser post-treatment provides local hardening of steel substrate, with no influence on diffusion layer chemistry. In a work we considered the structure, phase and chemical composition, microhardness of surface areas of steel P6M5 (substitute of PN SW7M, EN HS6–5–2) after chemical heat treatment: nitriding with further titanizing or chromizing and laser post-treatment. For this we used laser installation LATUS-31, radioelectron microscope REMMA 101A. The content of chemical elements was determined by EDS (heavy elements) and WDS (light elements) methods using REMMA 101A built-in facilities. Dry wear test was performed in sliding conditions using block-on-ring test layout. It is proved that combined coatings have better wear resistance versus coatings formed by common nitriding. Laser treatment of substrate prior to chemical heat treatment has a superior effect on the properties of diffusion coatings, increasing their wear resistance in order of two (compared with untreated coatings) Results of analysis indicate that nitrochromized coating on laser post-treated tool steel P6M5 has the best wear resistance under dry sliding friction.

PL

Nowoczesny materiał do produkcji narzędzi skrawających musi mieć dużą wytrzymałość mechaniczną, odporność na zużycie i efektywny stosunek ceny do jakości. Obecnie większość materiałów ma niewystarczającą odporność na zużycie, co powoduje brak narzędzi do cięcia materiałów. Skuteczną metodą wzmacniania stosunkowo niedrogich materiałów takich jak stal P6M5 i inne (substytut PN SW7M, EN HS6– 5–2) jest stosowanie ochronnych powłok dyfuzyjnych. Jedną z powszechnych metod obróbki cieplno-chemicznej jest azotowanie. Jednak taka obróbka ma szereg wad: długi czas trwania procesu, mała grubość powłoki, której duża twardość prowadzi do znacznego gradientu właściwości mechanicznych między warstwą dyfuzyjną a materiałem osnowy. Aby zredukować czas azotowania, proponujemy wstępną obróbkę laserową materiału podstawowego. Azotowanie z następującym nasyceniem tytanem i chromem pozwala dodatkowo poprawić właściwości skrawające stali P6M5. Jednak nasycenie metalu w temperaturze powyżej 1000°С prowadzi do całkowitego odpuszczania materiału osnowy pod badaną powłoką. Aby temu zapobiec, proponujemy przeprowadzenie obróbki laserowej po obróbce cieplno-chemicznej.

3

Fretting-Wear Mechanism of Textured Surfaces

Pashechko Mykhaylo, Marchuk Volodymyr, Kindrachuk Myroslav, Tisov Oleksandr, Kornienko Anatolii, Dukhota Oleksandr

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 3

186--191

EN

The wear mechanism of textured dimpled in conditions of lubricated fretting-wear is established, which, in contrast to others, takes into account possibility of removing deterioration products out of tribo-contact areas into dimples, preventing their action as abrasive material. Selection of optimal structural parameters of selectively dimpled areas allows to reduce duration of tribological couple running-in time. Depending on texture type, friction coefficient was reduced from 0.27 (for untreated furface) to 0.18, and wear loss – from 7.8 ×10–3g to 3.3 ×10–3g.

4

Research on the properties of Co-TiC and Ni-TiC HiP-sintered alloys

Cherepova Tetiana, Dmitrieva Galyna, Tisov Oleksandr, Dukhota Oleksandr, Kindrachuk Myroslav

Acta Mechanica et Automatica

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2019

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Vol. 13, no. 1

57--67

EN

Three types of sintered alloys were fabricated based on cobalt, nickel and high-temperature alloy ZhS32-VI matrix with titanium carbide strengthening phase. TiC content was in a range of 30–50 vol. %. The melting temperatures of alloys are higher than 1320°C, and they may undergo undamaged through all technological procedures together with turbine blades, including soldering and outgassing. DSC analyses indicates no additional thermal effects until melting, which confirms their structural stability. The examinations of microstructure revealed three types of constituents – TiC particles, matrix solid solution and blow outs – structural defects having negative effects on all the studied properties. It was found that heat resistance of nickel based sintered alloys at the temperature of 1100°C is superior as compared with the alloys based on cobalt and alloy ZhS32-VI. It has been established that wear resistance in conditions of fretting wear at temperatures of 20, 850, 950 and 1050°C of sintered alloy with ZhS32-VI matrix is mostly superior as compared with the other alloys. The properties of produced alloys allow to use them for manufacturing of components of friction couples operating in conditions of high temperature fretting wear, including protective pads of turbine blades top shrouds contact faces.