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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

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–ZnOnanocomposite (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.

3

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.

4

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.

5

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.

6

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.

7

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.

8

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.

9

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.

10

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.

11

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.

12

The Assessment of the Influence of the Material Used on the Wear And Tear of Forklifts and their Operational Safety

Grygier Dominika, Kęska Aleksandra

Tribologia

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2023

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nr 1

41--49

EN

The degree of wear of forklift forks is not always the effect of long operations or difficult operating conditions. The key parameter influencing the premature elimination of a vehicle from use is selecting an unsuitable material to make forks. Metallographic research allowed us to test the material structure and estimate which materials would allow us to extend the exploitation time of the forklift forks and, consequently, increase the operation safety level by excluding the inappropriate technical condition of a vehicle. The conducted research showed that the application of the properly selected heat treatment of steel allowed to obtain material characterised by high hardness and the lowest abrasion resistance, and simultaneously it accounted for the lowest fork wear level. Extending the standard macroscopic wear tests by microscopic tests may constitute an introduction to the research on standardising the material used to construct forklift forks.

PL

Stopień zużycia eksploatacyjnego wideł wózków widłowych nie zawsze jest wynikiem długiego okresu użytkowania czy trudnych warunków pracy pojazdu. Najistotniejszym parametrem, który wpływa na zbyt szybkie wykluczenie pojazdu z użytkowania jest dobór nieodpowiedniego materiału, z którego wykonane są widły. Wykorzystanie badań metalograficznych pozwoliło zbadać struktury materiałów i ocenić, która z nich pozwoliłaby wydłużyć okres eksploatacji wideł wózka widłowego, a w konsekwencji zwiększyłaby poziom bezpieczeństwa pracy, wykluczając niewłaściwy stan techniczny pojazdu. Przeprowadzone badania wykazały, że zastosowanie odpowiednio dobranej obróbki cieplnej stali umożliwia uzyskanie materiału charakteryzującego się wysoką twardością i najmniejszą odpornością na zużycie ścierne powierzchni, a jednocześnie odpowiada za najniższy poziom zużycia wideł. Poszerzenie standardowych badań oceny makroskopowej zużycia wideł o badania mikroskopowe może stanowić wstęp do badań nad znormalizowaniem rodzaju materiału używanego w konstrukcji wideł wózków widłowych.

13

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).

14

Badanie właściwości mechanicznych stali S355JR o różnych typach budowy mikrostruktury

Lipiec Sebastian

Stal, Metale & Nowe Technologie

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2023

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nr 1-2

36--40

PL

W artykule analizowana jest stal S355JR o różnych typach budowy mikrostruktury: poddana normalizacji, ze strukturą ferrytyczno-perlityczną (FP), oraz po wygrzewaniu austenityzującym, następnie chłodzona z dużą prędkością poprzez hartowanie w oleju, ze strukturą ferrytyczno-bainityczną (FB).

XX

An important aspect in the engineering design process is to know the true material characteristics of steels used in specific microstructures. These steels, depending on, among other things, heat treatment or working conditions and regimes, are characterised by a different microstructure. It is important to know the levels of both strength, ductility and fracture toughness of steels with different microstructure. This paper presents the results of an experimental study of S355JR steel with two types of microstructure: ferritic-perlitic and ferritic-bainitic. The basic strength and ductility characteristics of the steel determined by uniaxial tensile test and the results of fracture toughness tests are presented.

15

Dynamic Behaviour of Selective Laser Melted 316L Steel : Mechanical Properties and Microstructure Changes

Białobrzewski Paweł, Sienkiewicz Judyta, Janiszewski Jacek, Kluczyński Janusz

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2023

|

Vol. 14, Nr 2 (52)

51--72

EN

316L steel specimens with three different shear zones made by SLM (Selective Laser Melting) were subjected to dynamic tests using the Split Hopkinson Pressure Bar method. The effect of high-speed deformation on changes in microstructure was analyzed. In addition, the stress-strain relationship was determined from the SHPB results. To visualize the deformation process of the specimens during the tests, a camera with a high frame rate was used. It was shown that as the plastic deformation increases, the hardness of the material increases. Microstructural analysis of dynamically loaded areas revealed numerous defects. Twinning was found to be the main deformation mechanism. Large plastic deformation and many other microstructural changes such as shear bands, cracks and martensite nucleation were also observed.

PL

Próbki ze stali 316L z trzema różnymi strefami ścinania wykonane metodą SLM (Selective Laser Melting) poddano testom dynamicznym wykorzystując do tego metodę dzielonego pręta Hopkinsona (Split Hopkinson Pressure Bar). Przeanalizowano wpływ odkształceń o dużej szybkości na zmiany w mikrostrukturze. Ponadto na podstawie wyników badań SHPB wyznaczono zależność naprężenie- odkształcenie. W celu zobrazowania procesu odkształcania próbek podczas badań zastosowano kamerę o dużej częstości klatkowania. Wykazano, że wraz ze wzrostem odkształcenia plastycznego wzrasta twardość materiału. Analiza mikrostrukturalna obszarów obciążonych dynamicznie ujawniła liczne defekty. Stwierdzono, że głównym mechanizmem deformacji jest bliźniakowanie. Zaobserwowano również duże odkształcenia plastyczne i wiele innych zmian mikrostruktury, takich jak pasma ścinania, pęknięcia i zarodkowanie martenzytu.

16

Method of experimental study of the force-deformation characteristics of the Belleville spring of the stop assembly of a direct-flow gate valve

Hasanov Ilman I., Guliyev Agali A., Tanriverdiyev Yusif A.

Nafta-Gaz

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2023

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R. 79, nr 11

742--748

EN

The article presents research methods and appropriate equipment for conducting experiments, as well as the analysis of the results. Studies on the hardness of the microstructure, elastic deformation and parts and samples were carried out using hardness testers, microscopes PMT-3, MIM-8 and devices for measuring the “force-strain” characteristic. The results of the study wer used to establish the dependence of the elastic properties of Belleville springs on the heat treatment modes, while also determining the microstructure and layer depth using various research methods. Every work studying the elastic properties and measurement of the static compressive force of a spring at a given strain value has been studied theoretically. Depending on the operating conditions, disc springs can be installed singly or assembled into packages, forming an elastic element working under compression. The research materials will be used in the work to improve the tightness of straight-through valves and the durability of the shut-off assembly parts. The dependence of the spring compression force and its deformation on the geometrical parameters of the disc springs has been established. Comparison of experimental and theoretical dependences has been made. It has been established that the residual deformation of the Belleville spring after captivity has a negative effect on the tightness of the shut-off valve assembly. The influence of various technological processes and modes of thermal treatment of disc springs on their elastic properties has been studied. Practical recommendations for improving the technological process of thermal treatment of Belleville springs have been proposed. The tasks of further research and implementation of the obtained results have been determined. Search work has been carried out to improve the technology of hardening processing of parts of the shut-off unit (gate and seat) of direct-flow valves. The possibility of using accelerated nitrocarburizing in a triethanolamine medium with induction heating by high-frequency currents at a temperature range of 950°С for boriding and borochroming has been established. Samples were made from standard steel grades 40, 40Kh and 38Kh2MYuA, subjected to hardening by the considered methods, and a study was made of the hardness, depth and microstructure of the hardened layer. Research in this direction should be continued in order to study the tribological characteristics (friction coefficient and wear resistance) of hardened parts. Each operation of the spring manufacturing technology has been studied, and deviations that have a significant impact on the operation of the spring and the sealing of the shut-off valve assembly have been identified.

PL

Artykuł przedstawia metody badawcze i odpowiednie wyposażenie służące do przeprowadzania eksperymentów, a także analizę wyników. Badania przyprowadzono przy użyciu testerów twardości, mikroskopów PMT-3, MIM-8 oraz urządzeń do pomiaru charakterystyki “siła-odkształcenie”. Wyniki tych badań wykorzystano do ustalenia zależności właściwości elastycznych sprężyn Belleville od parametrów obróbki cieplnej, jednocześnie określając mikrostrukturę i głębokość warstwy za pomocą różnych metod badawczych. Każdy przypadek badania właściwości elastycznych i pomiaru statycznego siłowego odkształcenia sprężyny przy danej wartości odkształcenia był analizowany teoretycznie. W zależności od warunków pracy sprężyny tarczowe mogą być montowane pojedynczo lub w pakietach, tworząc element elastyczny podlegający ściskaniu. Materiały badawcze mogą zostać wykorzystane w pracach mających na celu poprawę szczelności zasuw oraz trwałości części zespołu zamykającego. Ustalono zależność między siłą kompresji sprężyny i jej odkształceniem a parametrami geometrycznymi sprężyn tarczowych. Dokonano porównania wyników eksperymentalnych i teoretycznych. Ustalono, że szczątkowe odkształcenie sprężyny Belleville po jej zamontowaniu ma negatywny wpływ na szczelność zespołu zaworu zamykającego. Zbadano wpływ różnych procesów technologicznych i trybów obróbki cieplnej sprężyn tarczowych na ich właściwości elastyczne. Zaproponowano praktyczne zalecenia w celu poprawy procesu technologicznego obróbki cieplnej sprężyn Belleville. Określono cele dalszych badań i sposób wdrożenia uzyskanych wyników. Przeprowadzono prace badawcze w celu poprawy technologii hartowania części zespołu zamykającego (zasuwy i gniazda) zasuw klinowych. Sprawdzono możliwość zastosowania przyspieszonego azotonawęglania w środowisku trietanoloaminy z indukcyjnym ogrzewaniem prądem o wysokiej częstotliwości w zakresie temperatury 950°C w procesie borowania i borochromowania. Wykonano próbki ze standardowych gatunków stali 40, 40Kh i 38Kh2MYuA, które poddano hartowaniu przy rozważanych metodach, przeprowadzono badanie twardości, głębokości i mikrostruktury warstwy hartowanej. Badania w tym kierunku powinny być kontynuowane w celu zbadania charakterystyk tribologicznych (współczynnika tarcia i odporności na zużycie) hartowanych części. Przeanalizowano każdą fazę technologii produkcji sprężyny i zidentyfikowano odchylenia, które mają znaczący wpływ na działanie sprężyny i uszczelnienie zespołu zaworu zamykającego.

17

Influence of laser and TIG cladding methods on microstructure morphology and hardness of Stellite 694 overlay deposited onto DS200+Hf alloy substrate

Gancarczyk Natalia, Gradzik Andrzej, Kościelniak Barbara, Gancarczyk Kamil, Góral Marek

Mechanik

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2023

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R. 96, nr 7

26--34

EN

In this paper the influence of cladding method - laser and TIG - on microstructure and properties of Stellite 694 coatings deposited onto DS200+Hf nickel based alloy substrate is presented. Manual TIG cladding process were carried out using LORCH V24 DC, laser cladding process was carried out using Yb:YAG, TruDisk 1000 TRUMPF. Cobalt alloy - Stellite 694 was used as a filler material. Effect of different cladding methods was examined based on chemical composition and microstructure analysis as well as hardness measurements of the deposited layers.

PL

W niniejszej pracy prowadzono ocenę morfologii składników fazowych mikrostruktury i właściwości warstwy ochronnej Stellite 694 na podłożu z żarowytrzymałego nadstopu niklu DS200+Hf, wytworzonej w procesach napawania elektrycznego (TIG) i laserowego. Napawanie elektryczne metodą TIG przeprowadzono z użyciem spawarki LORCH V24 DC, natomiast laserowe - za pomocą lasera dyskowego Yb:YAG, TruDisk 1000 firmy TRUMPF. Materiałem dodatkowym był stop kobaltu Stellite 694. Określono stopień oddziaływania źródła ciepła i warunków procesu na skład chemiczny napoiny, jej mikrostrukturę oraz twardość w mikroobszarach.

18

Studies of the microstructure of bimetallic titanium – austenitic steel joints obtained by explosive welding

Wachowski Marcin, Kosturek Robert

Materiały Wysokoenergetyczne

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2023

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T. 15

15--23

EN

The specific requirements of installations used in the chemical and petrochemical industries require materials with high corrosion resistance and adequate strength. Materials with these characteristics can be obtained by explosive cladding technology. Results of studies of the microstructure of titanium-austenitic steel 304L bimetallic joints in the welded and heat-treated condition are presented. Applications for this type of material include heat exchanger tube surfaces exposed to aggressive environments with high cyclical mechanical loads. The joints were tested using an optical microscope and a scanning electron microscopy. Heat treatment has contributed to a decrease in microhardness near the joint, which demonstrates a reduction in the strain hardening in this area.

PL

Szczególne wymagania instalacji stosowanych w przemyśle chemicznym i petrochemicznym powodują konieczność stosowania materiałów o dużej odporności korozyjnej oraz odpowiedniej wytrzymałości. Materiały spełniające te wymagania można wytworzyć technologią platerowania wybuchowego. W pracy przedstawiono wyniki badań mikrostruktury złączy bimetalicznych tytan-stal austenityczna 304L w stanie po zgrzewaniu i po obróbce cieplnej. Aplikacją tego typu materiałów są m.in. ściany sitowe wymienników ciepła, które narażone są na pracę w agresywnym środowisku, przy wysokich cyklicznych obciążeniach mechanicznych. Złącza badano z wykorzystaniem mikroskopu świetlnego oraz skaningowej mikroskopii elektronowej. Obróbka cieplna przyczyniła się do spadku mikrotwardości w pobliżu złącza, co świadczy o redukcji strefy umocnienia występującej w tym obszarze.

19

Study of the possibility of using sulfur asphalt and sulfur concrete in road construction

Bieliatynskyi Andrii, Yang Shilin, Krayushkina Kateryna, Shao Meiyu, Ta Mingyang

Materials Science Poland

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2023

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Vol. 41, No. 2

244--262

EN

The introduction of new effective road construction materials for pavements and foundations of highways is an urgent task, including the development and application of resource-saving technologies aimed at the use of low-demand, large-tonnage mineral materials, semi-finished products, industrial waste, and their by-products. Research on this topic has shown that sulfur and sulfur-containing waste, as well as modified technical sulfur when used as a binder, should be widely used in sulfur structural and road concrete in liquid, granular, or lumpy form. Ferrous cakes from the Pobug Nickel Plant or “tailings” of sulfur ore flotation can be used as fillers for sulfur binder. Having a high specific surface, they will have a positive effect on the structure formation of sulfur during the crystallization of the melt in the direction of strengthening the structure. Their high acid resistance should significantly increase the corrosion resistance of sulfur concretes. Granular slag from a metallurgical plant can be used as a fine aggregate. Overburden rocks in the form of gabbro-dolerites, dolerites, and basalts can be used as acid-resistant large aggregates. To reduce the fragility of the sulfur binder, plasticizing additives such as naphthalene, chlorinated paraffin, and bitumen can be introduced. The results obtained in this study confirm a decrease in the cost in the production of asphalt and cement concrete and the possibility of expanding the range of building materials with new road-building mixtures. Also, the test results showed that when temperature was decreased, the strength characteristics of sulfur concrete in the temperature range 0°C to −60°C increased by 7%. Low water absorption of sulfur concrete (0.1%–0.3%) versus cement concrete (2%–4%), which positively affected the strength and operational characteristics, was revealed.

20

Metallurgical aspects of the corrosion resistance of 7000 series aluminum alloys – a review

Lachowicz Marzena Małgorzata

Materials Science Poland

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2023

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Vol. 41, No. 2

159--180

EN

This article contains a review of selected studies conducted in the field of corrosion resistance of precipitation-hardenable 7000 series aluminum alloys. In particular, it discusses the effect of heat treatment and the role of thus formed microstructure on the corrosion behavior of these alloys. The article presents the three types of corrosion that occur most commonly in this group of materials in the context of their microstructure. It points to the importance of the chemical composition of a 7000 alloy, including the precipitates present in the microstructure, for the development of corrosion. The aluminum solid solution can act as an anode or cathode in relation to intermetallic particles. Such corrosion features may result in the destruction of the surfaces of elements made of the 7000 series aluminum alloy. It also raises the issue of the mechanism of corrosive destruction of the aluminum solid solution, which is connected with a crystallographic attack. In the case of this process, the nature of the micro-pits formed as a result of their local dissolution is related to the privileged dissolution of specific crystallographic planes and directions.