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1

Effect of Heat Treatment on Abrasion Wear Resistance of Steel with Micro-Additives of Boron and Vanadium

Białobrzeska Beata, Konat Łukasz

Tribologia

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2024

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nr 1

7--19

EN

This paper presents the results of own research regarding the role of microstructure and mechanical properties in the abrasive wear of metallic materials, demonstrated on the example of low-alloyed steel with microadditives of boron and vanadium. The first section discusses the current knowledge relating to the influence of microstructure and hardness on tribological conditions of materials. Further sections present the results of microstructure observations performed with light microscopy as well as with scanning electron microscopy and transmission electron microscopy. This research has focused on the material both in the as-delivered condition (directly after casting) and after heat treatment, which involved quenching and tempering at three temperatures: 200, 400, and 600°C. The tribological tests were performed with the use of the T-07 tribometer, in the presence of loose #90 electro corundum abrasive particles. The test results have been discussed and an attempt has been made to correlate them with the microstructure and selected mechanical properties. In order to identify wear mechanisms, the surfaces were visually inspected after the abrasion process. The inspection results indicate that the main wear mechanisms were microcutting and microploughing.

PL

W pracy zreferowano wyniki badań własnych w zakresie roli mikrostruktury i właściwości mechanicznych w zużywaniu ściernym materiałów metalicznych na przykładzie niskostopowego staliwa z mikrododatkami boru i wanadu. W początkowej części omówiono stan wiedzy dotyczący wpływu mikrostruktury i twardości na właściwości tribologiczne materiałów. Następnie przedstawiono wyniki obserwacji mikrostrukturalnych przeprowadzonych za pomocą mikroskopii świetlnej oraz elektronowej mikroskopii skaningowej. W referowanych badaniach skupiono się na materiale w stanie dostarczenia (bezpośrednio po odlewaniu) oraz na stanie obrobionym cieplnie, obejmującym hartowanie i odpuszczanie w trzech temperaturach, tj. 200, 400 i 600°C. Badania tribologiczne zostały przeprowadzone za pomocą testera T-07 w obecności luźnego ścierniwa, które stanowił elektrokorund #90. Wyniki badań zostały dodatkowe poszerzone o dyskusję oraz próbę ich korelacji z mikrostrukturą i wybranymi własnościami mechanicznymi. W celu ustalenia mechanizmów zużywania, dokonano obserwacji powierzchni po ścieraniu. Na tej podstawie stwierdzono, że głównymi mechanizmami zużycia były mikroskrawanie i mikrobruzdowanie.

2

Analysis of the Microstructure And Mechanical Properties of Duplex Steel Joints

Witkowska Małgorzata, Kowalska Joanna, Chronowska-Przywara Kinga

Tribologia

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2024

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nr 1

147--158

EN

The article presents a study, the aim of which was to analyze the microstructure and mechanical properties of welded joints of austenitic-ferritic duplex steel X2CrMnNiN21-5-1. This steel is characterized by good resistance to various types of corrosion, good strength properties and good weldability. Due to all these advantages, it is used in many industry sectors, and the main joining techniques are welding technologies. In this study, two joining techniques were used, SMAW (Shielded Metal Arc Welding) and GTA (Gas Tungsten Arc). The obtained welded joints were subjected to: macroscopic and microscopic metallographic tests, mechanical tests (static bending test and microhardness measurements), diffraction tests, and wear resistance tests. The results showed that the microhardness of the welds is similar and does not depend on the welding method used. In the microstructure of the analyzed joints there are two phases: austenite (γ) and ferrite (δ), with different morphologies depending on the welding conditions, which affect the phase transformations. Material wear within the weld is greater than in the base material.

PL

Celem badań była analiza mikrostruktury i własności mechanicznych złączy spawanych stali austenityczno-ferrytycznej typu duplex X2CrMnNiN21-5-1. Stal ta charakteryzuje się dobrą odpornością na różnego rodzaju korozje, dobrymi własnościami wytrzymałościowymi i dobrą spawalnością. Dzięki tym wszystkim zaletom znajduje zastosowanie w wielu gałęziach przemysłu, a głównymi technikami jej łączenia są technologie spawalnicze. W pracy zastosowano dwie techniki łączenia metodą SMAW (Shielded Metal Arc Welding) i GTA (Gas Tungsten Arc). Uzyskane złącza spawane poddano: badaniom metalograficznym makro- i mikroskopowym, badaniom mechanicznym (statyczna próba zginania i pomiary mikrotwardości), badaniom dyfrakcyjnym oraz badaniom odporności na zużycie. Wyniki badań pokazały, że mikrotwardości spoin są zbliżone i nie zależą od zastosowanej metody spawania. W mikrostrukturze analizowanych złącz występują dwie fazy austenit (γ) i ferryt (δ) o zróżnicowanej morfologii zależnej od warunków spawania, które wpływają na przemiany fazowe. Zużycie materiału w obrębie spoiny jest większe aniżeli w materiale rodzimym.

3

Selected microstructural phenomena in FSW joints

Wciślik Wiktor

Structure and Environment

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2024

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Vol. 16, no. 2

97--110

EN

The article is a literature review on selected phenomena leading to microstructural changes in material welded using the friction stir welding (FSW) method. Particular attention was paid to the phenomena of grains recrystallization, as well as dissolution and reprecipitation of second phase particles, resulting from temperature changes during FSW. Temperature transformations in different zones of the FSW joints were characterized. The role of base material phase transformation in the formation of new particles is discussed. In the tested aluminum alloys and stainless steels, this process was particularly intensified in the heat affected zone (HAZ). In areas subjected to high temperature and significant plastic deformation (nugget zone and thermomechanically affected zone), this phenomenon did not occur or was characterized by small intensity. It was indicated that the phenomenon of particle formation clearly affects the strength parameters of the joint.

PL

W artykule przedstawiono przegląd literatury dotyczący wybranych zjawisk prowadzących do zmian mikrostrukturalnych w metalach spawanych metodą zgrzewania tarciowego (FSW). Szczególną uwagę zwrócono na zjawiska rekrystalizacji ziaren oraz rozpuszczania i ponownego wytrącania cząstek drugiej fazy, zachodzące jako efekt zmian temperatury podczas FSW. Scharakteryzowano zmiany temperatury w różnych strefach złączy FSW. Omówiono rolę przemian fazowych materiału podstawowego w powstawaniu nowych cząstek. W badanych stopach aluminium i stalach nierdzewnych proces ten był szczególnie nasilony w strefie wpływu ciepła (SWC). W obszarach narażonych na działanie wysokiej temperatury i znacznych odkształceń plastycznych (jądro zgrzeiny i strefa uplastycznienia termomechanicznego) zjawisko to nie występowało lub charakteryzowało się niewielkim natężeniem. Wykazano, że zjawisko tworzenia cząstek wyraźnie wpływa na parametry wytrzymałościowe złącza.

4

Microstructural, antifungal and photocatalytic activity of NiO–ZnO nanocomposite

Wang Yixuan, Balakrishnan G.

Materials Science Poland

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2024

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Vol. 42, No. 1

107--115

EN

In this work, NiO–ZnO nanocomposite (NC) was prepared through a facile, low-temperature, sol–gel route. Zinc acetate dihydrate, nickel chloride hexahydrate, cetyltrimethyl ammonium bromide (CTAB), and citric acid were used in the synthesis of the material. Then, the sample was kept in the muffle furnace at a temperature of 600°C for 2 h. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), UV–Visible spectroscopy, and photocatalytic and antifungal investigations were used to characterize the synthesized nanocrystallites. The XRD data showedthe polycrystalline hexagonal ZnO nanoparticles and cubic NiO crystallites. FTIR studies confirmed the presence of Zn-O and Ni-O bonds in the sample. The FESEM analysis showed the morphology of nanocrystallitescharacterized by their homogeneous shape and size. The absorbance curves from the UV–Visible spectroscopy investigation revealed the bandgap of 3.17 eV. The research findings demonstrate that the NiO–ZnO NC possesses the significant level of selected microbial pathogens. Industrial dyesmake water unhealthy for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable, and causes a severe threat to human health and environmental safety. Hence, it is necessary to develop efficient and environmentally friendly technology to remove MB from wastewater. The ZnO–NiO NC degraded the MB dye pollutant under visible irradiation (125 W), according to photocatalytic tests. After 120 min of exposure, the photocatalytic investigations demonstrated 75% degradation efficiency.

5

Evaluation of cracking risk of 80MnSi8-6 nanobainitic steel during hot forging in the range of lower temperature limits

Lisiecka-Graca Paulina, Lisiecki Łukasz, Zyguła Krystian, Wojtaszek Marek

Materials Science Poland

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2024

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Vol. 42, No. 1

171--185

EN

Nanobainitic steels exhibit an exceptional combination of high strength, good plasticity, impact toughness, and wear resistance. They are suitable for the production of large mass components through the open-die forging process. Subsequently, the forgings are air-cooled. An obstacle of this method is the extended time required for the large forgings to undergo a bainitic transformation, making the industrial implementation of this process economically unjustifiable. Nevertheless, nanobainitic steels also allow for the open-die forging of small batches of structural elements with high property requirements. A technological limitation lies in the necessity of performing a series of operations, leading to a prolonged processing time dependent on the shape of the product and the degree of deformation. Therefore, inter-operational reheating is often necessary, incurring costs and time consumption. This is particularly relevant to forgings with a mass ranging from a few to several dozen kilograms, which, due to their low thermal capacity, rapidly dissipate heat to the surroundings and tools. Designing an economical process with a limited number of reheating cycles requires advanced knowledge of material behavior under thermo-mechanical deformation parameters, including boundary conditions where a significant decrease in plasticity occurs and the risk of crack initiation. To obtain this information, a comprehensive analysis of the influence of thermo-mechanical parameters applied during the deformation of nanobainitic steel at relatively low temperatures on the flow characteristics and crack formation was conducted. To achieve this goal, the Digital Image Correlation method, the finite element method modeling considering damage criteria, and the macrostructural evaluation of deformed specimens were employed.

6

Comparative analysis of microstructure and selected properties of WC-Co-Cr coatings sprayed by high-velocity oxy fuel on S235 and AZ31 substrates

Jonda Ewa, Myalska-Głowacka Hanna, Łatka Leszek, Szymański Krzysztof, Dziekońska Małgorzata

Materials Science Poland

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2024

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Vol. 42, No. 1

32--41

EN

The purpose of this work was to carry out comparative studies of WC-Co-Cr coatings deposited using the high velocity oxy fuel (HVOF) method onto two types of substrate material: structural steel S235 and magnesium alloy AZ31. The influence of the substrate material type on the microstructure, phase composition, crystallite size, porosity, Vickers microhardness, instrumental hardness (HIT), Young’s modulus (EIT), and fracture toughness was investigated. For both substrates, the deposited coatings deposited were characterized with fine-grained and compact microstructure. The X-ray diffraction (XRD) revealed presence of following phases: WC, W2C, Co0.9W0.1, and Co3W9C4. The WC phase was the most desirable and stable one with crystallites were below 100 nm. On the other hand, the size of the W2C crystallites was below 30 nm. The coatings obtained showed porosity values equal to 2.3 ± 0.4 vol% and 2.8 ± 0.7 vol% for AZ31 and S235, respectively. The average Vickers microhardness for both types of sample was appproximately 1200 HV0.3. The average HIT values for carbide particles and metallic matrix were around 29 GPa and 6.5 GPa, respectively. In the case of EIT, it was around 620 GPa and 190 GPa for WC and Co-Cr, respectively. The differences between coatings were negligible. The EIT value for both coatings was equal to 344 ± 11 GPa. The fracture toughness was around 4.5 MPa · m1/2 in both cases. The investigations revealed that it is possible to replace steel substrate material with a much lighter equivalent, in this case AZ31 alloy, without deterioration of the coating properties.

7

Microstructural study of the composite nickel based, containing different Al amounts, sintered by an unconventional technique and forged

Bendriss Houceme, Boudebane Said, Lemboub Samia, Benselhoub Aissa

Inżynieria Materiałowa

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2024

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Vol. 45, nr 3

8--17

EN

The aluminum-enriched composite with the composition of Udimet 720 alloy was developed using an unconventional two-step sintering process. The first occurred at 1380°C for 0.5 h and the second at 1180°C for 3 h. The sintered material was then forged at 1200°C under a load of 50 kG and with a fall height of 220 mm, in order to achieve the clusters fragmentation of hard components, followed by the homogenization annealing at 800°C for 1.5 h. The consolidation technique included solution treatment at 1080°C and aging at 800°C with various holding times. The investigation techniques by X-ray diffraction analysis (XRD) and observations under a scanning electron microscope (SEM) with semi-quantitative analyses (EDS) have offered the possibility to reveal the aluminum addition’s impact and the holding time aging on the material’s microstructural evolution. The sintered alloy with a high Al content (5.25 %) exhibits a complex structure composed of metallic matrix γ, the chromium carbide Cr23 C6 , and a large variety of binary intermetallics. Despite this, the solution treatment caused an almost complete dissolution of these compounds, and consequently, a saturation of the nickel cubic lattice. An increase in precipitation phenomenon was, due to the formation of the intermetallic γ’ (Ni, Co)3 (Al, Ti), and then, the alloyed chromium carbide (Cr, Co, Ni, Mo, Ti)23 C6 , led to a noticeable hardening of the metal matrix, reaching a microhardness of 700 HV0.1.

PL

Opracowano kompozyt wzbogacony aluminium o składzie stopu Udimet 720 w niekonwencjonalnym dwuetapowym procesie spiekania. Kompozyt spiekano w temp. 1380°C przez 0,5 h, a następnie w temp. 1180°C przez 3 h. Spiekany materiał poddano kuciu w temp. 1200°C pod obciążeniem 50 kG i wysokości opadania 220 mm, w celu uzyskania fragmentacji skupień twardych składników, a następnie wyżarzaniu homogenizującym w temp. 800°C przez 1,5 h. Technika konsolidacji obejmowała obróbkę przesycającą w temp. 1080°C i starzenie w temp. 800°C z różnymi czasami przetrzymywania. Techniki badawcze polegające na analizie dyfrakcji promieni rentgenowskich (XRD) i obserwacje pod skaningowym mikroskopem elektronowym (SEM) wraz z analizami półilościowymi (EDS) umożliwiły ujawnienie wpływu dodatku aluminium i czasu utrzymywania starzenia na ewolucję mikrostruktury materiału. Spiekany stop o wysokiej zawartości Al (5,25%) wykazywał złożoną strukturę, na którą składały się: metaliczna osnowa γ, węglik chromu Cr23 C6 i duża różnorodność binarnych związków międzymetalicznych. Mimo to obróbka roztworowa spowodowała niemal całkowite rozpuszczenie tych związków, a w konsekwencji nasycenie sześciennej sieci niklu. Nasilenie zjawiska strącania osadów spowodowane utworzeniem się międzymetalicznego γ' (Ni, Co)3 (Al, Ti), a następnie stopowego węglika chromu (Cr, Co, Ni, Mo, Ti)23 C6 , doprowadziło do zauważalnego utwardzenia osnowy metalicznej, osiągającego mikrotwardość 700 HV0,1.

8

Popożarowe zmiany strukturalne w złączach spawanych stali niestopowych

Klimek Marcin, Pańcikiewicz Krzysztof

Inżynieria i Budownictwo

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2024

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R. 80, nr 3

128--132

PL

W artykule poruszono zagadnienie wpływu pożaru na zmiany w strukturze i właściwościach mechanicznych złączy spawanych elementów ze stali niestopowych. Analizie poddano procesy zachodzące podczas spawania, mające wpływ na uzyskiwaną wejściową strukturę i właściwości w spoinie i strefie wpływu ciepła. Na tej bazie dokonano zwięzłej analizy wpływu niskotemperaturowego i wysokotemperaturowego pożaru oraz sposobu jego gaszenia na zmiany w strukturze i właściwościach mechanicznych złączy spawanych stali niestopowych. Zarekomendowano prowadzenie ekspertyz popożarowych stalowych konstrukcji spawanych.

EN

In the article deals with the issue of the impact of fire on changes in the structure and mechanical properties of welded joints of non-alloy steel elements. The processes occurring during welding, affecting the obtained input structure and properties in the weld and in the heat affected zone, were analyzed. On this basis, a concise analysis of the impact of low- and high-temperature fire and the method of extinguishing it on changes in the structure and mechanical properties of welded joints of non-alloyed steels was made. Recommendations for conducting post-fire expertise of welded steel structures are included.

9

The effect of magnesium and copper addition on the microstructure, mechanical properties, and corrosion rate of as-cast biodegradable zinc alloys

Gieleciak Magdalena, Janus Karol, Maj Łukasz, Petrzak Paweł, Bieda Magdalena, Jarzębska Anna

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 3

art. no. e149175

EN

Microstructure, mechanical, and corrosion properties of as-cast pure zinc and its binary and ternary alloys with magnesium (Mg), and copper (Cu) additions were investigated. Analysis of microstructure conducted by scanning electron microscopy revealed that alloying additives contributed to decreasing average grain size compared to pure zinc. Corrosion rate was calculated based on immersion and potentiodynamic tests and its value was lower for materials with Cu content. Moreover, it was shown that the intermetallic phase, formed as a result of Mg addition, constitutes a specific place for corrosion. It was observed that a different type of strengthening was obtained depending on the additive used. The presence of the second phase with Mg improved the tensile strength of the Zn-based materials, while Cu dissolved in the solution had a positive effect on their elongation.

10

Thermophysical properties and microstructure of 32CrMoV12-28 hot-work tool steel

Koniorczyk Piotr, Zieliński Mateusz, Sienkiewicz Judyta, Zmywaczyk Janusz

Archives of Thermodynamics

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2024

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Vol. 45, no 2

269--277

EN

Measurements of thermal diffusivity, heat capacity and thermal expansion of hot work tool steel 32CrMoV12-28 have been carried out in the temperature range from room temperature (RT) to 1000℃. 32CrMoV12-28 steel has been tested for military applications as steel for gun barrels. The thermophysical properties of this steel can be used as input data for numerical simulations of heat transfer in gun barrels. Both the LFA 427 laser flash apparatus in the RT 1000℃ temperature range and the LFA 467 light flash apparatus in the RT 500℃ temperature range were used for thermal diffusivity tests. Specific heat capacity was investigated in the range RT 1000℃. The specific heat was determined by two methods, i.e. the classical method, the so-called continuous-scanning method and the stepwise-scanning method according to EN ISO 11357-4. The paper compares both methods and assesses their suitability for testing the specific heat capacity of barrel steels. Thermal expansion was investigated in the range RT 1000℃. Inconel 600 was selected as the reference material during the thermal diffusivity test using LFA 467. Light microscopy (LM), scanning electron microscopy (SEM), and Vickers microhardness measurements were performed to detect changes in the microstructure before and after thermophysical measurements. We compared the results of measurements of the thermophysical properties of 32CrMoV12-28 steel with the results of our tests for other barrel steels with medium carbon content, i.e. X37CrMoV5-1 (1.2343), 38HMJ (1.8509) and 30HN2MFA. The comparison was made in terms of shifting the effect of material shrinkage towards higher temperatures.

11

Remelting of Aluminum Scrap Into Billets Using Direct Chill Casting

Rajagukguk Kardo, Suyinto Suyinto, Saptoadi Harwin, Kusumaningtyas Indraswari, Arifvianto Budi, Mahardika Muslim

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 1

40--49

EN

An as-cast aluminum billet with a diameter of 100 mm has been successfully prepared from aluminum scrap by using direct chill (DC) casting method. This study aims to investigate the microstructure and mechanical properties of such as-cast billets. Four locations along a cross-section of the as-cast billet radius were evaluated. The results show that the structures of the as-cast billet are a thin layer of coarse columnar grains at the solidified shell, feathery grains at the half radius of the billet, and coarse equiaxed grains at the billet center. The grain size tends to decrease from the center to the surface of the as-cast billet. The ultimate tensile strength (UTS) and the hardness values obtained from this research slightly increase from the center to the surface of the as-cast billet. The distribution of Mg, Fe, and Si elements over the cross-section of the as-cast billet is inhomogeneous. The segregation analysis shows that Si has negative segregation towards the surface, positive segregation at the middle, and negative segregation at the center of the as-cast billet. On the other hand, the Mg element is distributed uniformly in small quantities in the cross-section of the as-cast billet.

12

Characteristics of High-Strength Cast Steel Micro-Alloyed with Vanadium

Białobrzeska Beata

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 1

66--79

EN

This article presents the results of research into the characteristics of cast steel alloyed with chromium and vanadium, subjected to heat treatment for increased strength parameters. In the first part, it discusses the state-of-the-art knowledge regarding technological developments in the field of cast-steel alloys and the influence of individual alloying additives on the microstructure and the properties of the steel alloy. Further sections present the results of microstructure observations performed with light microscopy, scanning electron microscopy, and transmission electron microscopy. This research focuses on the material in the state directly after casting and after heat treatment, which involved quenching and tempering at 200 °C. The microstructural analysis performed as part of this research has informed the discussion of the results obtained from tensile and impact strength tests. The article also includes the results of a fractography analysis performed as the final part of the tests and offers a general summary and conclusions.

13

The Influence of the Hot Working Tool Steel Substrate Material on the Element Distribution, Microstructure and Hardness of Gas Metal Arc Welding Hardfaced Layers

Lachowicz Marzena M., Sokołowski Paweł, Kaszuba Marcin

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

320--333

EN

The paper presents the results of Gas Metal Arc Welding (GMAW) hardfacing testing performed on three grades of hot working tool steels, namely: 55NiCrMoV7, X37CrMoV5-1 and modified X38CrMoV5-3 grade. Metallographic investigations, mainly microstructural ones, were carried out and hardness profiles were analyzed. The chemical composition was investigated in each individual layer of the hardfaced deposits and the substrate material, in order to obtain a profile representation. The obtained results of profilometric evaluation of the chemical composition showed clear differences in the content of basic and alloying elements in the subsequent weld layers. The diversity of the chemical composition of the substrate material caused that the uniform chemical composition for all tested materials was achieved only in the third, upper weld layer. Despite the variable content of alloying elements and carbon, as well as slight differences in microstructure occurring for individual weld layers, a substantially stable and high hardness was maintained over the entire cross-section of the obtained hardfaced coatings. In the area of the heat-affected zone (HAZ), a decrease in hardness was observed, which is associated with the decomposition of the high-temperature tempered martensite and the spheroidization of the microstructure.

14

The Effect of HVOF Spray Distance on Solid Particle Erosion Resistance of WC-based Cermets Bonded by Co, Co-Cr and Ni Deposited on Mg-alloy Substrate

Jonda Ewa, Łatka Leszek, Lont Aleksandra, Gołombek Klaudiusz, Szala Mirosław

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 2

115--128

EN

Magnesium alloys are very interesting engineering materials because of their high strength-to-density ratio. On the other hand, they are characterized by low hardness as well as low erosion resistance. Because of these reasons, their applications in the industry are very limited. The article presents the results of the high velocity oxy-fuel (HVOF) spraying of the hard cermet coatings onto AZ31 magnesium alloy substrate. Three feedstock powders were used in the process with composition (wt.%): WC-12Co, WC-10Co-4Cr and WC-20Cr3C2Ni. The spray distance (SD) was selected as a variable parameter with values equal to 320 and 400 mm. Observations carried out under a scanning electron microscope (SEM) revealed a typical HVOF-sprayed microstructure with a compact structure and low porosity (below 3 vol.%). The hardness of the manufactured coatings, ranging from 912 HV0.2 to 1328 HV0.2, what was significantly higher than the substrate. The solid particle erosion tests were carried out according to the ASTM G76-04 standard. Erosive experiments were done for 30°, 60° and 90° inclination angles of the nozzle using Al2O3 abrasive. Erosion tests confirm that cermets exhibit substantial erosion resistance better than the substrate. The highest erosion resistance was noted for WC-10Co-4Cr coatings. The erosion rate for cermet coatings was mostly below 0.9 mg/min, whereas for the AZ31 it was more than 1.5 mg/min. In the case of the average erosion value, it was between 12 and 22 times lower than for the substrate. Results analysis reveal that shorter spray distance decreases porosity, increases hardness, and finally supports erosion resistance of the cermets.

15

Investigations of the Effect of Heat Treatment and Plastic Deformation Parameters on the Formability and Microstructure of AZ91 Alloy Castings

Majerski Krzysztof, Siemionek Ewa, Szucki Michał, Surdacki Piotr

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

1--9

EN

The article discusses the influence of heat treatment and metal forming parameters on formability and the structure of the AZ91 cast magnesium alloy. The aim of the article is to determine the optimal parameters of homogenization and plastic deformation of sand castings made of the AZ91 alloy in order to improve their properties and structure. In this study, sand castings made from the AZ91 alloy were examined. In the first stage, the castings were homogenized at: 385°C, 400°C, 415°C and 430°C with argon as a shielding gas for 24 hours and then quenched. Subsequently the upsetting tests were conducted at 380 C; 400 C; 420 C; 440 C for two deformation values: ε=0.7 and ε=1.1. After upsetting, the samples were water- and air-cooled. At this stage, a visual assessment was made and samples without cracks were subjected supersaturation at 415 C for 6 h, and artificial aging at 175 C for 24 h. Vickers microhardness tests and microstructure assessment were carried out, at individual stages of testing. Based on the results obtained from the upsetting, structure and hardness tests, the most favorable homogenisation and plastic deformation conditions were determined for AZ91 alloy sand castings. The best results are achieved by homogenizing sand castings at 415 °C for 24 h. Among the tested parameters for conducting metal forming processing in the range of 380-440 °C and deformation values: ε=0.7 and ε=1.1, forging of sand-cast AZ91 magnesium alloy at 420 °C and deformation of ε=0.7 with water cooling seems to be the most favourable. The final heat treatment applied after the deformation process consists of supersaturation at 415 °C for 6 hours water quenching as artificial aging at 175 °C for 24. This combination of heat and plastic treatment parameters of castings allows for improvement of the structure and properties of sand castings made of the AZ91 alloy.

16

Enhanced Concrete Performance and Sustainability with Fly Ash and Ground Granulated Blast Furnace Slag – A Comprehensive Experimental Study

Cheruvu Rajasekhar, Rao Burugupalli Kameswara

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 3

161--174

EN

This research paper explains in detail how well regular concrete works and how well concrete with fly ash and ground granulated blast furnace slag (GGBS) as a substitute for cement. Through a series of experiments, the objective of the study is to perform an experimental approach that promote the usage of partial replacement-based concrete that can replace the conventional concrete and to promote the sustainable development. a dedicated methodology is developed for the study, focussing on the mechanical and durability properties of the materials with inducing sustainable materials. The methodology study examines at the mechanical properties, durability, and microstructural attributes of the concrete blends. Cement concrete specimens with binder ratios (%) of 0.3, 0.4, and 0.5 were tested for compressive strength, rapid chloride permeability, SEM, and XRD at 28, 56, and 90 days. Fly ash and GGBS were used to partially replace cement at 0% to 70% for all binder ratios by weight of cement. There were optimal replacement percentages for each binder ratio and fly ash and GGBS partially substituted concrete had similar or enhanced mechanical properties to conventional concrete. The novelty of the study is to incorporate microstructure analysis for the same samples that shall enable to analyse the behaviour of the partial replaced materials with conventional concrete. In connection with the results, the study had found lower RCPT values in partial replacement concrete specimens, fly ash and GGBS increased chloride ion resistance. SEM and XRD analyses revealed the concrete mixtures' microstructural properties and phase composition, showing how supplementary cementitious materials refine pore structure and provide durable hydration products. This study shows that fly ash and GGBS can improve concrete performance and reduce impact on environment and applications in construction.

17

Assessment of High-Temperature Oxidation Properties of 316L Stainless Steel Powder and Sintered Porous Supports for Potential Solid Oxide Cells Applications

Kabir Ahsanul, Koszelow Damian, Miruszewski Tadeusz, Tinti Victor Buratto, Kern Frank, Molin Sebastian

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 5

10--18

EN

In this work, oxidation properties of austenitic 316L stainless steel powder and sintered porous support were investigated at the temperature range of ~600-750 °C for 100 hours in ambient air. Oxidation kinetics was determined by continuous thermogravimetry and analyzed employing parabolic rate law. It was observed that oxidation leads to the formation of an oxide scale, with substantial oxidation occurring at ≥ 650 °C in the powder. The porous steel support was fabricated by tape casting method with two distinct pore former concentrations. The microstructural features of both the powder and support were investigated by X-ray diffractometry and scanning electron microscopy coupled with energy-dispersive X-ray analysis. The mechanical properties of the metal support were examined before and after oxidation via a microhardness test. The effect of porosity on the resulting properties of the metal support was also highlighted. In summary, 316L stainless steel support suits SOCs applications below 600 °C.

18

Analysis of the Surface Topography of Fractures Caused by Static and Impact Bending of Polypropylene and Polyamide PA6 Reinforced with Continuous Glass Fibers

Głowacka Karolina, Małecka Joanna, Smolnicki Tadeusz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 5

51--64

EN

The work analyzes the fracture topography of composite specimens subjected to three-point bending - static and impact. Scanning electron microscopy was used for this purpose. The tests were performed for two different materials - polypropylene and polyamide PA6, each reinforced with unidirectional glass fibers. In one case, the fibers were distributed evenly, and in the other, there were areas more and less reinforced with fibers. It was observed that in all cases the tension and compression parts could be clearly distinguished. However, for different materials and with different methods of destruction, different failure mechanisms were observed, noted based on the analysis of the fracture topography. It was observed that regardless of the loading method and material, in the tensile part there were visibly protruding fibers, and in the compressed part it was the matrix, not the fibers, that was destroyed. In the case of statically loaded samples, damage occurred at the macrostructural level, and in the case of dynamically loaded samples, at the microstructural level. Additionally, samples with uneven fiber distribution were more susceptible to delamination.

19

The effect of the austenitisation temperature for the two-stage heat treatment of high-manganese steels on its wear resistance under abrasive conditions

Dziubek Mateusz, Rutkowska-Gorczyca Małgorzata, Grygier Dominika

Tribologia

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2023

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nr 3

19--29

EN

Fine-grained high-manganese X120Mn12 grade steel was subjected to a two-stage heat treatment consisting of long-term isothermal annealing at 510°C, which was followed by resaturation in order to reduce the negative effect of the brittle carbide carbides of manganese cementite (Fe,Mn)3 C. The objective of the experiment was to elucidate the effects of distinct stages of heat treatment on the properties of high manganese steel with regard to its resistance to abrasive wear. Supersaturation was performed for eleven different variations of temperature values ranging from 600°C to 1100°C to verify its effect on the resistance to abrasion wearunder abrasion conditions. An increase in the supersaturation temperature results in the gradual coagulation and disintegration of the colonies of pearlite and needle-like carbides (Fe,Mn)3 C formed during isothermal annealing. At the same time, as a result of the PSN (particle stimulated nucleation) process, the microstructure of austenite undergoes partial refinement, which ultimately increases the resistance to abrasive wear. As a result of the final microstructural changes resulted in an increase in the resistance to abrasion of approximately 6% compared to the initial state.

PL

Drobnoziarnistą stal wysokomanganową gatunku X120Mn12 poddano dwustopniowej obróbce cieplnej złożonej z długoterminowego izotermicznego wygrzewania w temperaturze 510°C, a następnie ponownemu przesycaniu w celu zredukowania negatywnego wpływu kruchych wydzieleń węglików cementytu manganowego (Fe,Mn)3 C. Eksperyment miał na celu poznanie wpływu poszczególnych etapów obróbki cieplnej na właściwości stali wysokomanganowej w kontekście odporności na zużycie ścierne. Etap przesycania zrealizowano dla jedenastu różnych wariantów wartości temperatury z zakresu od 600°C do 1100°C w celu zweryfikowania jej wpływu na odporność na zużycie ścierne. Wzrost temperatury przesycania skutkuje stopniową koagulacją oraz rozpadem powstałych w trakcie wyżarzania izotermicznego kolonii perlitu oraz iglastych węglików (Fe,Mn)3 C. Jednocześnie w wyniku procesu PSN (ang. particles stimulated nucleation) mikrostruktura austenitu ulega częściowemu rozdrobnieniu, co finalnie wpływa na wzrost odporności na zużycie ścierne. W wyniku końcowych zmian mikrostrukturalnych uzyskano wzrost odporności na ścieranie o około 6% w porównaniu do stanu wyjściowego dla wariantu obróbki cieplnej złożonego z etapu długoterminowego izotermicznego wyżarzania w temperaturze 510°C oraz następującego po nim przesycania w temperaturze 750°C. Wzrost odporności wywołany został wydzieleniem globularnych węglików (Fe,Mn)3 C oraz powstaniem nowych ziaren austenitu.

20

The correlation between microstructure, mechanical and tribological properties in the alloys of Co-Cr protectors with micro additives Mo and W

Augustyn-Nadzieja Joanna, Frocisz Łukasz, Matusiewicz Piotr

Tribologia

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2023

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nr 3

7--17

EN

The paper presents the results of tests of tribological wear of two Co-Cr-Mo alloys (Wironit LA) and Co-Cr-Mo-W (Colado CC) used to make skeletal prostheses, combined works, implants and metal frameworks for ceramics. The test samples were centrifugally cast using the lost wax method and subjected to hardness measurements, microscopic observations, and a quantitative description of the microstructure. SEM examinations and EDS analysis of micro-areas on dendritic arms and interdendritic areas were performed together. The abrasive wear resistance tests with the use of a T-05 tester in the friction system roller-block were conducted in a dry sliding contact under the conditions of a metal-metal contact with the load of 100 N and for two friction paths, 500 and 1000 m.

PL

W pracy przedstawiono wyniki badań zużycia tribologicznego dwóch stopów Co-Cr-Mo (Wironit LA) i Co-Cr-Mo-W (Colado CC) stosowanych do wykonywania protez szkieletowych, prac kombinowanych, implantów i szkieletów metalowych pod ceramikę. Badane próbki odlewano odśrodkowo metodą wosku traconego i poddawano pomiarom twardości, obserwacjom mikroskopowym wraz z ilościowym opisem mikrostruktury. Wykonano badania SEM wraz z analizą EDS mikroobszarów na ramionach dendrytycznych oraz obszarów interdendrytycznych. Badania odporności na zużycie ścierne z wykorzystaniem testera T-05 w układzie ciernym wałek–blok przeprowadzono w suchym styku ślizgowym w warunkach kontaktu metal–metal z obciążeniem 100 N i dla dwóch dróg tarcia, 500 i 1000 m.