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1

Effect of shells number and machining on selected properties of 3D-printed PLA samples

Kowalska Natalia, Szczygieł Paweł, Skrzyniarz Michał, Błasiak Sławomir

Polimery

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2024

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Vol. 69, nr 3

186--190

EN

Effect of shells number (1–5) on tensile properties of PLA samples printed using the FDM/FFF technique was investigated. The crack surface was also analyzed. The best properties were obtained for 4-shell sample. However, due to the large coefficient of variation (>> 10%) in the case of elongation, 3-shell sample was selected for testing the machining impact. Such a large coefficient of variation can be explained by the presence of voids between the layers. The greater the number of layers, the greater the structure defects. Machining increases surface smoothness while reducing tensile strength and practi¬cally unchanged elongation at break.

PL

Zbadano wpływ liczby warstw (1–5) na właściwości mechaniczne przy rozciąganiu próbek PLA otrzymanych techniką FDM/FFF. Analizie poddano także powierzchnie pęknięć. Najlepsze właściwości uzyskano dla próbki 4-warstwowej. Jednak, ze względu na duży współczynnik zmienności (>> 10%) w przypadku wydłużenia, do badań wpływu obróbki skrawaniem wytypowano próbkę 3-warstwową. Tak duży współczynnik zmienności można wyjaśnić obecnością pustych przestrzeni pomiędzy warstwami. Im większa liczba warstw, tym większe defekty struktury. Obróbka skrawaniem zwiększa gładkość powierzchni przy jednoczesnym zmniejszeniu wytrzymałości na rozciąganie i praktycznie niezmienionym wydłużeniu przy zerwaniu.

2

Ocena wpływu parametrów otrzymywania biokopoli(estro-eterów) na wydajność procesu ich syntezy

Paszkiewicz Sandra, Walkowiak Konrad, Irska Izabela, Piesowicz Elżbieta, Bajor Alicja, Baszak Karolina, Damiri Fouad, Berrada Mohammed

Przemysł Chemiczny

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2023

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T. 102, nr 12

1394--1404

PL

Trzy PHF-blok-PTMO kopoli(estro-etery) oparte na surowcach odnawialnych otrzymano metodą polikondensacji w stanie stopionym w różnych warunkach temperaturowych. Wykazano wpływ parametrów procesu syntezy na wartości granicznej liczby lepkościowej, właściwości mechaniczne i termiczne. Wykazano, że możliwy jest dobór parametrów i warunków syntezy w celu uzyskania odpowiednich właściwości użytkowych materiałów w zależności od potrzeb i przyszłych zastosowań.

EN

Three PHF-block-PTMO copoly(ester-ethers) based on renewable raw materials were synthesized by melt polycondensation at 225-240°C. The effect of synthesis parameters on the limiting viscosity number as well as mech. and thermal properties was detd. In particular, Young modulus, tensile strength, elongation at yield, strength at break, elongation at break, limited viscosity no., density and crystallinity degree of the copolymers were detd. as a function of temp. The copolymer synthesized at 235°C showed the highest limited viscosity no. and thus mol. mass. It exhibited superior mech. properties.

3

The effect of natural fillers on the mechanical properties and flammability of low-density polyethylene

Samujło Bronisław

Polimery

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2023

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Vol. 68, nr 7-8

396--402

EN

The effect of 10-40 wt% natural fillers (pumpkin husks, bean sorting waste, pine sawdust) on the mechanical properties and flammability of LDPE was examined. As the filler content increased, the hardness slightly increased and the tensile strength and relative elongation decreased. The tensile modulus more than doubled (pumpkin husks, pine sawdust). The linear combustion rate increased unfavorably, but the assumed flammability class HB40 was achieved, except for LDPE filled with 40 wt% pine sawdust (HB75). At the same time, the temperature in the combustion area decreased in the vertical flammability test.

PL

Zbadano wpływ naturalnych napełniaczy (łuski dyni, odpady sortownicze fasoli, trociny sosnowe) stosowanych w ilości 10-40% mas. na właściwości mechaniczne i palność LDPE. Wraz ze wzrostem zawartości napełniacza nieznacznie zwiększała się twardość, a zmniejszała wytrzymałość na rozciąganie i wydłużenie względne. Moduł sprężystości przy rozciąganiu zwiększył się ponad dwukrotnie (łuski dyni, trociny sosnowe). Niekorzystnie wzrosła liniowa szybkość spalania, ale uzyskano zakładaną klasę palności HB40, poza LDPE z dodatkiem 40% mas. trocin sosnowych (HB75). Jednocześnie obniżyła się temperatura w obszarze spalania w pionowym teście palności.

4

Research on the Knittability of Metallic Yarns in the Warp-knitted Mesh of a Deployable Antenna

Haiyan Xu, Nanliang Chen, Jinhua Jiang

Fibres & Textiles in Eastern Europe

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2023

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Vol. 31, no. 2

51--55

EN

Metallic yarns are difficult to be knitted. To resolve the problem, the paper used the knitted yarn strength utilization factor to quantitatively characterize knittability, which was the ratio of yarn strength after being knitted to that of the original yarns. Furthermore, the relationship between the yarns’ basic mechanical properties and the knitted yarn strength utilization factor was investigated by testing the yarns’ basic mechanical properties. The results showed that it was feasible to quantitatively characterize the yarns’ knittability using the knitted yarn strength utilization factor. And also the breaking strength of yarn was not correlated with the knittability. The elongation at break of the yarn was positively correlated with knittability. The bending stiffness of the yarn was negatively correlated with the knittability. Finally, a multiple linear regression model of the knittability and the mechanical properties of the yarn was developed. The model showed that there was a significant linear relationship between knittability and the elongation of yarns at break and the bending rigidity of yarns, with the bending stiffness of yarns being more significant.

5

The Effects of Friction Stir Welding Parameters on Microstructure, Fatigue Life and Tensile Properties of Aluminum 2024-T3 Alloy

Şık Aydın, Özer Alpay

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

499--505

EN

In this study, Al 2024-T3 alloy plates were joined by using friction stir welding. Welding was performed at a rotational speed of 930, 1450, 2280 rpm and a welding feed rate of 180 mm min-1. The welded samples were analyzed at the microstructural level. Moreover, both bending fatigue tests and tensile tests were performed on samples. At the end of the microstructural examination of the samples welded at the rotational speed of 930 rpm and the welding feed rate of 180 mm min-1, the formation of tunnel defects was observed. The highest fatigue life was obtained at 2280 rpm and 180 mm min-1. The lowest fatigue life was obtained at 930 rpm and 180 mm min -1. The highest ultimate tensile stress was obtained at 2280 rpm/180 mm min-1 sample, which shows about a 12% reduction relative to the base material. The lowest ultimate tensile stress was obtained at 930 rpm/180 mm min-1 sample. The ultimate tensile stress value of the 930 rpm/180 mm min-1 sample decreased by approximately 25%.

6

Study on Tensile Properties and Microstructures of Different Sites in Al-Si Alloy Casting Component

Tao Jianquan, Xiang Lin, Chen Xidong, Sun Jipeng, Wang Yanbin, Du Chuanhang, Peng Feifei, Gao Shiqing, Chen Qiang

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

585--589

EN

The tensile properties and microstructures of ZL114A alloy component with a complex shape are investigated at room temperature and 200°C, using the tensile tests, scanning electron microscopy and electron backscattering diffraction. Both thin wall and thick structure exhibit excellent properties, of which max ultimate tensile strength and elongation at break reach 314 MPa and 2.5% at room temperature, respectively. The ultimate tensile strengths of thin wall are 40 MPa and 25 MPa greater than those of thick structure at room temperature and 200°C, respectively. Moreover, the eutectic Si phases of thin wall exhibit a predominantly spherical morphology while of the morphology of thick structure are rod-like, resulting in the different mechanical properties between thin wall and thick structure. The fracture morphologies of thin wall and thick structure are studied to explain the difference in performance between thin wall and thick structure.

7

Effects of SPD by Biaxial Alternate Forging on the Tensile Properties and Microstructure of AZ31B Magnesium Alloy

Shin Young-Chul, Ha Seong-Ho, Shah Abdul Wahid

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 1

97--101

EN

The forming limit of AZ31 alloy, a representative Mg-Al-Zn-based wrought alloy, and the effect of severe plastic deformation (SPD) by examining the microstructure change caused by dynamic recrystallization led by high temperature and high dislocation density at 300℃ using a biaxial alternate forging (BAF) were investigated in this study. As a result of BAF test for AZ31 Mg alloy, significant cracks on the ends of workpieces occurred after 7 passes. The microstructure of as-extruded specimen showed the non-uniform distribution of the relatively coarse grains and the fine grains considered to be sub-grains. However, as the number of passes increases, the area of coarse grains gradually disappeared and the fine grains became more dominant in the microstructures. The result of tensile test for workpieces with each forging pass showed an increase in strength depending on pass number was shown with a slight increase of elongation. The Electron Backscatter Diffraction (EBSD) results exhibited that, the microstructure showed the presence of coarse grains and twins after only 1 pass, while the grains appeared to be significantly refined and uniformly distributed after 3 pass, at which the strength and elongation began to increase, simultaneously.

8

Influence of Rare Earth Sm Addition on Microstructure and Tensile Properties of Al-Si-Cu 319 Alloy

Patel D. N., Sutaria Mayur P.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 1

25--33

EN

In the present investigation, the influence of addition of the rare earth element samarium (Sm) in different concentrations (0, 0.1, 0.3, 0.5, 0.7 and 0.9wt.%) on the microstructure and tensile properties of the Al-Si-Cu 319 alloy have been evaluated. Microstructural constituents such as SDAS of α-Al and characteristics of eutectic silicon particles were observed by optical microscopy. It was concluded from the findings that Sm addition reduces the size of secondary dendrite arm spacings (SDAS) and altered the morphology of the eutectic silicon particles from needle-like to lamellar and smaller segments. The tensile properties of the Al-Si-Cu 319 alloy improved with the concentration of Sm. It was found that the highest tensile properties were obtained at 0.7wt.% addition of Sm, i.e., 55.5% higher than unmodified 319 alloy. With the further addition of the Sm above 0.7wt.%, it does not improve the tensile properties of the alloy. This can be attributed to the precipitation of the brittle and needle like quaternary Sm-rich intermetallic compounds observed through Scanning electron microscopy.

9

Comparison of Tensile Properties of Nb Grain Refined A206 Alloy by Gravity and Tilt Casting

Palamutcu Nuri, Dizdar Kerem Can, Sahin Hayati, Dispinar Derya

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

49--53

EN

Turbulent filling of a mould is one of the ways to introduce extrinsic defects into the cast part that could deteriorate many properties of any casting. The turbulence can be easily eliminated by counter gravity casting. In gravity casting, tapered downsprue, tapered runner is needed such that the mould cavity is filled counter-gravity from the bottom which is the only best way to eliminate turbulence during filling. Tilt casting method also exists which has the potential to quiescently transfer the liquid into the mould cavity. In this work, gravity and tilt casting methods were used to evaluate the tensile properties of Nb grain refined 206 alloy. Three different Nb contents were investigated: 0.025, 0.05 and 0.1 wt% ratios and it was found that 0.05 wt% revealed the highest tensile properties. On the other hand, when the intrusion of surface folded oxides was eliminated during filling, it was found that mechanical properties were increased significantly, and particularly, the toughness was increased by two folds when tilt casting was applied compared to gravity casting.

10

Reinforcement of compatibilized nanoclay/Inviya fibers to epoxy‑based glass fiber nanocomposites for high‑impact strength applications

Shelly Daksh, Nanda Tarun, Mehta Rajeev

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e84, 2023

EN

This research work is the first successful trial in which silanized nanoclay and compatibilized Inviya fibers were reinforced in epoxy-based glass fiber reinforced composites (EGFCs) resulting in significant improvements in impact strength without degrading tensile properties. Vacuum assisted resin infusion moulding (VARIM) technique was used for processing of multi-scale filler reinforced EGFCs. Inviya fibers were used, because of their high ‘elastic recovery’ and ‘stretchability’ (five times the original length) due to alternative flexible and rigid molecular structure. Nanoclay and Inviya fibers were subjected to compatibilization with different surface treatments. Compatibilization of fillers was confirmed through Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy-Energy-dispersive spectroscopy (FE-SEM/EDS) analysis. Nanoclay dispersion and morphology in EGFCs was ascertained through X-ray diffraction (XRD) and Transmission electron microscopy (TEM) analysis. Reinforcement of compatibilized Inviya fibres (First Method: maleic anhydride grafting, and Second Method: combination of phosphoric acid treatment followed by silanization) enhanced the impact strength by 132% and 150%, respectively, over the reference composition. FE-SEM micrographs of fracture surface of impact test specimens were utilized to identify the mechanisms causing improvement in impact behaviour.

11

The effect of basalt knitted fabric on the properties of green epoxy resin

Jamshaid Hafsa, Rajput Abdul Waqar, Zahid Bilal, Memon Sanam, Qureshi Raja Fahad, Aslam Sarmad, Nadeem Muhammad

Polimery

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2022

|

Vol. 67, nr 2

67--71

EN

The influence of basalt fabric on the tensile mechanical properties and the impact resistance of green epoxy resin was investigated. Composites with parallel arrangement of insert yarns had better properties than in the case of their perpendicular arrangement. The properties were also influenced by the number of layers of the fabric. The tensile strength and impact resistance of the composites were better than the commercially available side mirror covers due to the superior properties of the basalt fiber.

PL

Zbadano wpływ tkaniny bazaltowej na właściwości mechaniczne przy rozciąganiu i odporność na uderzenie „zielonej” żywicy epoksydowej. Kompozyty o równoległym ułożeniu przędzy charakteryzowały się lepszymi właściwościami niż te o prostopadłym ułożeniu. Na właściwości miała również wpływ liczba warstw tkaniny. Wytrzymałość na rozciąganie i odporność na uderzenie kompozytów były lepsze niż dostępnych na rynku osłon lusterek bocznych ze względu na dobre właściwości włókna bazaltowego.

12

Comparative analysis of cold and warm rolling on tensile properties and microstructure of additive manufactured Inconel 718

Zhang Tao, Li Huigui, Gong Hai, Wu Yunxin, Ahmad Abdulrahaman Shuaibu, Chen Xin, Zhang Xiaoyong

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e44, 2022

EN

Despite the high efficiency and low cost of wire + arc additive manufacture (WAAM), the epitaxial grown columnar dendrites of WAAM deposited Inconel 718 cause inferior properties and severe anisotropy compared to the wrought components. Fundamental studies on the influence of one-pass cold and warm rolling on hardness and microstructure were investigated. Then the interpass cold and warm rolling on tensile properties were also analyzed. The results show that the one-pass rolling increases the hardness and displays a heterogeneous hardness distribution compared to the as-deposited material, and the warm rolling exhibits a larger and deeper strain compared to cold rolling. The columnar dendrites gradually change to cell dendrites under the rolling process and then change to equiaxed grains with the subsequent new layer deposition. The average grain size is 16.8 μm and 23.5 μm for the warm and cold rolling, respectively. The strongly textured columnar dendrites with preferred < 001 > orientation transform to equiaxed grains with random orientation after rolling process. The grain refinement contributes to the dispersive distributed strengthening phases and the increase in its fraction with heat treatment. The as-deposited samples show superior tensile properties compared to the cast material but inferior compared to the wrought components, while the warm-rolled samples show superior tensile properties to wrought material. Isotropic tensile properties are obtained in warm rolling compared to cold rolling. The rolling process and heat treatment both decrease the elongation and lead to a transgranular ductile fracture mode. Finally, the rolling-induced strengthening mechanism was discussed.

13

Effect of heat treatment on the tensile properties of incrementally processed modified polylactide

Kozik Bogdan, Dębski Mariusz, Bąk Piotr, Gontarz Małgorzata, Zaborniak Małgorzata

Polimery

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2021

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T. 66, nr 6

357--361

EN

The influence of temperature (80, 95 and 110°C) and annealing time (20, 25, 30 min) on the tensile strength and elongation at break of the modified polylactide (PLA Pro) processed by 3D printing (FFF – Fused Filament Fabrication) was investigated. The properties of PLA Pro were compared with properties of unmodified PLA and ABS. It was observed that the tensile strength was comparable for all annealed samples and was about 45 MPa. Moreover, the annealing process decreased the tensile strength of the modified PLA and increased the elongation at break, which may be related to a change in the degree of crystallinity. The modified PLA was characterized by tensile properties similar to ABS.

PL

Zbadano wpływ temperatury (80, 95 i 110°C) i czasu wygrzewania (20, 25, 30 min) na wytrzymałość na rozciąganie i wydłużenie względne przy zerwaniu modyfikowanego polilaktydu (PLA Pro) przetwarzanego metodą druku 3D (FFF – Fused Filament Fabrication). Właściwości PLA Pro porównano z właściwościami niemodyfikowanego PLA i ABS. Zaobserwowano, że wytrzymałość na rozciąganie była porównywalna dla wszystkich próbek i wynosiła około 45 MPa. Ponadto, proces wygrzewania spowodował zmniejszenie wytrzymałości na rozciąganie modyfikowanego PLA i zwiększył wydłużenie przy zerwaniu, co może być związane ze zmianą stopnia krystaliczności. Modyfikowany PLA charakteryzował się właściwościami mechanicznymi przy rozciąganiu podobnymi do ABS.

14

Application of Artificial Neural Network to Predict the Tensile Properties of Dual-Phase Steels

Shin Seung-Hyeok, Kim Sang-Gyu, Hwang Byoungchul

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 3

719--723

EN

An artificial neural network (ANN) model was developed to predict the tensile properties of dual-phase steels in terms of alloying elements and microstructural factors. The developed ANN model was confirmed to be more reasonable than the multiple linear regression model to predict the tensile properties. In addition, the 3D contour maps and an average index of the relative importance calculated by the developed ANN model, demonstrated the importance of controlling microstructural factors to achieve the required tensile properties of the dual-phase steels. The ANN model is expected to be useful in understanding the complex relationship between alloying elements, microstructural factors, and tensile properties in dual-phase steels.

15

The decisive impact of microstructure on the machinability of pure copper

Sun Xiaoxiang, Ebrahimi Mahmoud, Attarilar Shokouh

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

852--860

EN

Ultrafine-grained (UFG) materials have been of great attention due to their considerable behavior compared to coarse-grained counterparts. Also, the machinability of these UFG materials is of great importance because of the machining significance in manufacturing the final shape of industrial components. Hence, this study dealt with machinability in relation to the microstructure and mechanical properties of the UFG pure copper processed by the twist extrusion. The remarkable microstructure evolution through the dynamic recrystallization mechanisms improved the tensile strengths and hardness of the twist extrusion processed pure copper. Also, the reduction of ductility in the UFG copper compared to the initial state was related to the change of tensile fractography mechanism in which the large and deep dimples transformed into the combined small and shallow dimples with some cleavage planes in the UFG copper. Furthermore, the enhanced machinability of the processed sample was related to its lower thermal conductivity and the development of strain localization within the narrow shear bands which lead to the production of discontinuous short chips. Hence, the formation of the UFG structure is a suitable option to attain the enhanced machinability behavior of copper as one of the most used metals.

16

Processing routes, resulting microstructures, and strain rate dependent deformation behaviour of advanced high strength steels for automotive applications

Nanda Tarun, Singh Vishal, Singh Gurpreet, Singh Manpreet, Kumar B. Ravi

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

112--135

EN

Automobile industry is continuously striving to obtain light body-in-white structures to meet tightened regulations on flue-gas emissions/crash-testing parameters. ‘Advanced high strength steels (AHSS)’ find increased applications in the automotive industry because of improved crashworthiness/formability at reasonably low costs. AHSS category mainly includes transformation induced plasticity (TRIP) steels, twinning induced plasticity (TWIP) steels, dual phase (DP) steels, complex-phase (CP) steels, and quenching-partitioning (Q&P) steels. AHSSs provide superior strength-ductility combination than conventional high-strength steels by virtue of their multi-phase microstructures. Mechanical properties of AHSSs are greatly influenced by processing routes/derived microstructures. Furthermore, mechanical properties/tensile deformation behavior are also strain rate dependent. During an automobile crash, deformation occurs at strain rates which are exceedingly higher than quasi-static conditions. So, investigation of AHSS properties under both quasi-static as well as high strain rates conditions is important to check applicability for superior crash-resistance. The present work critically reviews details of processing routes, room temperature microstructures, mechanical properties, and finally strain rate dependence of tensile deformation behaviour of AHSSs. Finally, main gaps in existing literature/scope for future research with regards to high strain rate deformation dependent properties of this steel category are presented.

17

Physico-mechanical and thermal properties of thermoplastic poly(vinyl alcohol) modified thermosetting urea formaldehyde resin

Sultana Shahin, Mannan Mehedi, Abedin Md. Jaynal, Islam Zahidul, Nur Husna Parvin, Samaddar Purabi Rani

Advances in Materials Science

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2021

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Vol. 21, nr 4(70)

53--66

EN

Urea formaldehyde (UF) resins are brittle and to improve their tensile properties poly(vinyl alcohol) (PVA) has been used to modify the UF resin. An easy improved procedure was developed to make PVA modified UF resin on the basis of conventional synthesis of UF resin. Prepolymer of UF was mixed with different weight percentages of PVA (1-5%) to synthesize modified UF resin which can be used to make adhesive for forest products. Both UF and modified UF resins were characterized by FTIR, physico-mechanical and thermal properties analyses. Modified UF resin containing 2 wt. % PVA exhibited better results than the UF.

18

Discussion on the Tensile and Bending Properties of PAN-based Pre-oxidised Fibre Felt Composite Materials

Liu Yuanjun, Bao Wenli, Zhao Xiaoming

Fibres & Textiles in Eastern Europe

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2020

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Vol. 28, no. 2 (140)

57--60

EN

The impact of the mass percentage of PAN-based pre-oxidised fibre felt in a composite material and of the curing temperature on the composite material’s mechanical properties were studied in order to optimise the preparation method of epoxy resin composite material. The results showed that when the dosage of PAN-based pre-oxidised fibre felt was 15% of the mass of epoxy resin and the curing temperature was 170 °C, the tensile and bending properties of the composite materials produced were the best. This study has addressed the absence of reports on this type of composite material, and is expected to lead to the development of applications for this new type of composite material.

PL

W celu zoptymalizowania metody przygotowania materiału kompozytowego z żywicy epoksydowej zbadano wpływ procentu masy wstępnie utlenionego filcu z włókien PAN w materiale kompozytowym i temperatury utwardzania na właściwości mechaniczne materiału kompozytowego. Wyniki pokazały, że najlepsze właściwości rozciągania i zginania wytwarzanych materiałów kompozytowych otrzymano dla 15% ilość wstępnie utlenionego filcu z włókien PAN w stosunku do masy żywicy epoksydowej, a optymalna temperatura utwardzania wynosiła 170 °C. Autorzy pracy oczekują, że przeprowadzone badanie doprowadzi w przyszłości do opracowania aplikacji dla nowego rodzaju materiału kompozytowego.

19

Analysis of tensile properties of worn fabric conveyor belts with renovated cover and with the different carcass type

Andrejiova Miriam, Grincova Anna, Marasova Daniela

Eksploatacja i Niezawodność

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2020

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Vol. 22, no. 3

472--481

EN

Conveyors are the means of transportation used in many industries. The load-bearing and tractive component of a belt conveyor is a conveyor belt which consists of a carcass and cover layers. During an operation, belts are exposed to loads that cause damage to the belts. It is therefore necessary to ensure that a conveyor belt possesses required mechanical properties during the transport of material. The key mechanical properties of a conveyor belt are tensile properties. They are significantly affected by the fabric carcass of a conveyor belt. The tensile properties of conveyor belts are largely affected by the carcass materials. They are also affected by the types of fibres in the longitudinal (warp) and transverse (weft) directions of the fabric carcass because the carcass transfers all tensile stresses of the conveyor belt. A fabric conveyor belt is regarded as a composite material, consisting of the carcass (polyamide P and polyamide-polyester EP) and the cover layers. The costs of a conveyor belt represent 10-30 % of the price of the entire conveyor. It is therefore reasonable to prefer only those conveyor belts that show the properties prescribed by relevant norms. The subject of the article is worn conveyor belts with renovated top cover (renovated conveyor belts). The tensile properties are used to assess the suitability for further use of renovated conveyor belts in practice. The article presents the analysis of tensile properties of renovated fabric conveyor belts in relation to the carcass type. The observed results were compared applying the DOE method, regression and correlation analysis, and the method of statistic induction. All the conclusions, made based on the above-listed methods, are identical for the examined tensile properties. The results indicate that the examined tensile properties of conveyor belts have not undergone any significant change after the renovation of the top cover layer.

PL

Przenośniki taśmowe znajdują zastosowanie jako urządzenia transportowe w wielu gałęziach przemysłu. Nośnym i pociągowym elementem przenośnika taśmowego jest taśma transportowa, która zbudowana jest z rdzenia i okładek. Podczas pracy, taśmy narażone są na obciążenia, które prowadzą do ich uszkodzenia. Dlatego konieczne jest aby taśma transportująca materiał posiadała wymagane właściwości mechaniczne. Kluczowymi właściwościami mechanicznymi taśmy przenośnikowej są właściwości wytrzymałościowe. Zależą one w dużym stopniu od tkaninowego rdzenia taśmy, a w szczególności od rodzaju materiałów, z których jest zbudowany, oraz typu włókien wchodzących w skład jego osnowy (biegnących w kierunku wzdłużnym) i wątku (w kierunku poprzecznym), jako że to właśnie rdzeń przenosi wszystkie naprężenia rozciągające taśmy przenośnika. Tkaninową taśmę transportową uważa się za materiał kompozytowy, składający się z rdzenia (poliamid P i poliamid–poliester EP) oraz warstw wierzchnich (okładek). Koszty taśmy stanowią 10–30% ceny całego przenośnika, dlatego do użycia powinno dopuszczać się jedynie takie taśmy przenośnikowe, które wykazują właściwości określone w odpowiednich normach. Przedmiotem artykułu są zużyte taśmy przenośnikowe z odnowioną górną okładką (odnowione taśmy przenośnikowe). Właściwości wytrzymałościowe wykorzystano do oceny przydatności odnowionych taśm do dalszego wykorzystania w warunkach praktycznych. W artykule przedstawiono analizę właściwości wytrzymałościowych odnowionych taśm tkaninowych w funkcji typu rdzenia. Zaobserwowane wyniki porównano stosując metodę DOE, analizę regresji i korelacji oraz metodę indukcji statystycznej. Wszystkie wnioski uzyskane w oparciu o wyżej wymienione metody są identyczne dla badanych właściwości wytrzymałościowych. Wyniki wskazują, że badane właściwości wytrzymałościowe taśm przenośnikowych nie ulegają istotnej zmianie po renowacji górnej okładki.

20

Kumar Sanjeev, Pandey Chandan, Goyal Amit

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 3

506--532

EN

This paper investigates the metallurgical behavior and mechanical properties of the P91 steel welds joint. The joint of heat-resistant P91 steel has been welded by the gas tungsten arc welding (GTAW) process using the dissimilar Inconel grade 617 filler. The P91 welds joints have been subjected to varying heat treatment regimes in the temperature range of 650–810 °C for 2 h. The normalizing-based tempering was also performed for the welded joint. The weld fusion zone (WFZ) with austenitic structure and heat-affected zones (HAZs) with martensitic structure was characterized using the optical microscope and scanning electron microscope (SEM). The detailed characterization of the weld metal and HAZ interface has also been performed for as-welded and post-weld heat treatment (PWHT) conditions. For mechanical properties of the welds joint, tensile testing and hardness testing were performed. The relationship between mechanical behavior and microstructure of the welded joint has been evaluated for as-welded and heat treatment conditions. The microstructure studies revealed the formation of an unmixed zone (UZ) close to the fusion line, and it was characterized as peninsula and island. The WFZ showed the complete austenitic mode of the solidification and revealed the austenitic structure with cellular and equiaxed grains in the center of the weld metal. The columnar and cellular dendrites were seen near the boat fusion line, i.e., interface of the weld metal and HAZ. The soft δ ferrite patches were observed near the fusion line in the area of HAZ and remain undissolved up to tempering temperature of 810 °C (PW 3). The dissolution of the ferrite patches was noticed for PW 4. The maximum and minimum tensile strength of the welds joint was measured 731 MPa and 502 MPa for PW 3 and PW 2, respectively. A uniform hardness variation in the transverse direction of the welded joint was observed for PW 3 and PW 4 conditions. The optimum combination of strength and ductility was obtained for the PW 3 condition.