Publikační činnost Katedry mechanické technologie / Publications of Department of Mechanical Technology (345)

Permanent URI for this collectionhttp://hdl.handle.net/10084/64764

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Katedry mechanické technologie (345) v časopisech registrovaných ve Web of Science od roku 2003 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

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Now showing 1 - 20 out of 107 results

Application of bandage repair systems in the power sector to restore pipeline integrity
(Elsevier, 2024) Kozák, Jindřich; Krejčí, Lucie; Hlavatý, Ivo; Bučko, Michal; Hloch, Sergej; Fryšák, Martin; Srivastava, Madhulika; Viňáš, Ján; Vašek, Martin
This work explores the possibility of repairing damaged pressure piping systems using composite repair bandaging technology. Loctite technology from Henkel was selected from several existing methods and applied at the weld joint. To assess the performance of the bandage, a bore was made at the weld joint to simulate a replacement defect of the composite bandage. The bandage, along with the welded joints, was subjected to microstructural and macrostructural analysis, and mechanical and fire resistance tests were also performed. Based on the obtained results, it is concluded that the properties of the Loctite composite system are suitable for repairing pressure piping in the power industry. However, it is not always possible to use this repair method due to certain boundary conditions for its application, such as maximum pipe overpressure, the temperature of the internal medium and the environment, degradation of the repair system due to the medium being transferred and the environment, reduction of the pipe wall at the repair site, possible surface treatment before application of the system, etc. For these reasons, the repair system may be used for a temporary period (approved by the power plant operator), and the spot will then be repaired in the standard way by replacing parts of the pipeline during a planned equipment shutdown.
Quality of zinc coating formed on structural steel by hot-dip galvanizing after surface contamination
(MDPI, 2024) Vontorová, Jiřina; Mohyla, Petr; Kreislová, Kateřina
This paper deals with the evaluation of the surface of structural steel whose samples were deliberately contaminated with transparent spray primer, adhesive label glue, and welding sprays prior to hot-dip galvanizing. The galvanized samples were studied by optical microscopy, GDOES, adhesion tests, and condensation humidity tests. The effect of surface contamination on the quality of the zinc coating was found to be significant. In some cases, the zinc coating is damaged (after contamination with welding sprays), in others, it is completely absent (after contamination with spray primer or adhesive label glue).
Influence of pulsed current GTAW-WAAM process parameters on the single layer bead geometry and multi bead multi-layer deposition of a nickel-based superalloy
(Elsevier, 2024) Kumar, M. D. Barath; Arivazhagan, N.; Tofil, Szymon; Andersson, Joel; Kozák, Jindřich; Manikandan, M.
Wire + arc additive manufacturing (WAAM) is a state-of-the-art and highly efficient technique utilized to produce near net-shaped products on a large scale, employing a layer-by-layer approach. This research used pulsed current mode welding for single-layer bead-on-plate experiments to optimise the process parameters for WAAM of Hastelloy C-276. The effect of process parameters including pulsed current, pulsed frequency, and pulse duty cycle was systematically investigated on the weld appearance, depth of penetration, layer width, and layer height. The optimisation of single layer experimental runs was conducted using Box-Behnken designs (BBD) and the response surface method to construct several regression models. An analysis of variance was employed to validate the accuracy of both the measured and generated models. The BBD results indicate that interactions have a more significant impact on the peak current parameter than the resulting impact of pulse duty cycle and frequency. Validation tests were performed on the model with the optimal process variables that were identified, and its mechanical and metallurgical properties were analysed. Macrostructure and microstructural analysis of the single layer showed that the specified process parameters led to acceptable base metal fusion and bead is free from cracking. There was a considerable decrease in elemental segregation while using the pulse mode technique. Finer grain structure and reduced microsegregation enhance the hardness. Further residual stress (RS) at weld bead and base plate was 213 MPa and -240 MPa. Nonhomogeneous heat transfer during welding affects RS compressive and tensile characteristics. WAAM printing quality requires precise control of LH, LW, and DOP. This research aimed to propose suitable parameter values for manufacturing WAAM component for usage in chemical processing, nuclear, marine, and industrial settings by using unique pulsing features.
Properties of gradient layers obtained through HVOF spraying and Plasma cladding
(MM Science, 2024) Ochodek, Vladislav; Szymura, Michał
The study discussed in the article aimed to identify the obtainability of a gradient layer made by the High-Velocity Oxygen Fuel (HVOF)-spraying of an NiAl-based coating between a layer made using the plasma cladding process and powder Stellite 6 and a substrate made of structural steel S355JR. Overlay welds obtained in related tests were made using various process parameters as well as various values of current, travel speeds and powder feed rates. The study also involved the performance of macro and microscopic metallographic tests, hardness measurements as well as the analysis of the chemical and phase composition of gradient layers.
Effect of twist-channel angular pressing on precipitation in Al–Mg–Zn–Ga alloys
(Springer Nature, 2024) Stan-Głowińska, Katarzyna; Rogal, Łukasz; Wójcik, Anna; Hilšer, Ondřej; Rusz, Stanislav; Greger, Miroslav; Maziarz, Wojciech
The influence of severe plastic deformation, namely twist-channel angular pressing on the formation of quasicrystalline precipitates in Al-Mn-Zn-Ga alloy, was investigated. The deformation process was performed at two temperatures: 473 K (200 degrees C) and 433 K (160 degrees C). The microstructure of alloys after the process was analyzed in terms of the number density of formed precipitates, their size, and crystals structure. Mechanical properties including hardness and compression yield strength were determined. The obtained results indicated that at higher temperature (473 K), crystalline precipitates were formed. Additionally, the number density of the formed precipitates decreased with subsequent passes. At lower temperature, 433 K, the formed precipitates have quasicrystalline structure. Alloys processed at 433 K exhibit yield strength two times higher than in the previous case which correlates well with higher number density of precipitates estimated for these samples.
Design and optimization of production line layout using material flows
(MDPI, 2024) Bučko, Michal; Krejčí, Lucie; Hlavatý, Ivo; Lorenčík, Jiří
Businesses are constantly trying to improve their production by looking for bottlenecks to improve their market position. The introduction and innovation of automated production lines is necessary for both labor shortages and productivity and quality reasons. A combination of precision, fluidity, and speed, that is the basic definition of a production line. With the advent of new technologies, production lines have also begun to continuously speed up and innovate. Innovation is the subject of this paper, where the problem of designing a completely new layout for a new production line in the food industry has been addressed. The aim of this paper was to create a design for the optimal layout of the production line in preselected production areas. Optimal use of the space allocated for production is very important for every company today.
Blank material influence on stamping springback
(MM Science, 2024) Čada, Radek; Tiller, Petr; Hikade, Antonín
This paper concerns the evaluation of blank material Influence on springback of Irregularly shaped stamping after drawing operation to keep the dimensions and tolerances of stamping after the drawing process which are given in part drawing. Simulation of the drawing process and consequent stamping springback were carried out by PAM-STAMP 2GTM software which uses the finite elements method, with the use of blanks from strip steels DX54D, HC220P, HX220BD and HX220YD. Two mesh strategles for drawing tool parts In the software PAM-STAMP 2GTM were compared. Stamping springback was evaluated with the use of a reference points system. Critical areas of deformations and stamping springback were evaluated. Simulation results were compared with measurements on real stampings. The most sultable strip steel in terms of achieving the minimum size of springback after stamping drawing was evaluated.
Surface pretreatment of selectively laser melted 316L stainless steel substrate and its effect on the quality of the vitreous enamel coating
(MM Science, 2024) Sternadelová, Kristýna; Krupová, Hana; Hajnyš, Jiří; Měsíček, Jakub; Mohyla, Petr
This paper examines various surface pretreatments and their impact on the quality of vitreous enamel coating. In this case, 316L stainless steel was chosen as the base material and a premix enamel coating specially prepared for stainless steel for enamelling. Samples prepared by Selective Laser Melting (SLM) were used. Both mechanical (blasting, tumbling) and chemical (pickling) pre-treatments were applied. The surface variation of the differently prepared samples together with the interface between the vitreous enamel coating and the base material were examined by SEM. The results show that different surface pretreatments affect the final enamel coating and its quality.
Influence of temperature and number of passes during twist channel angular pressing (TCAP) on the microstructural, mechanical, and corrosion properties of Mg-4Li-Ca
(Springer Nature, 2024) Bednarczyk, Iwona; Dobkowska, Anna; Hilšer, Ondřej; Rusz, Stanislav; Pastrňák, Martin; Čada, Radek; Jabłońska, Magdalena; Tkocz, Marek; Kowalczyk, Karolina; Palgan, Daria; Nečas, David; Mizera, Jarosław
In this study, the possibilities of improving the mechanical and corrosion properties of Mg-4Li-1Ca processed using twist channel angular pressing (TCAP) were investigated. There was a special focus on the optimization of the TCAP parameters through analyzing how the temperature of TCAP influences the microstructural, mechanical, and corrosion properties of the alloy, and how an increasing number of TCAP passes affects these properties. It was shown that among specimens extruded with one pass, the highest mechanical properties were achieved at 180 degrees C. Microstructural changes were noted at higher temperatures and caused a decline in the mechanical properties. The influence of an increasing number of passes through the TCAP channel was rather minor and did not lead to significant microstructural strengthening. In contrast, the best corrosion performance was observed after four passes at 180 degrees C and after a single pass at 300 degrees C. The results of this study show that TCAP is an efficient method for the grain refinement of hcp-structured metals, lowering the costs of the plastic deformation of Mg-based alloys.
Analysis of non-conforming production in an engineering company
(Sveučilište Josipa Jurja Strossmayera u Osijeku. Strojarski fakultet; Elektrotehnički fakultet; Građevinski fakultet., 2024) Schindlerová, Vladimíra; Marčík, Jan; Čada, Radek; Šajdlerová, Ivana
In practice, there is a very often inaccurate recording of nonconforming production, resulting in waste and increasing wastefulness. This has a direct impact on the efficiency and profitability of production. This article deals with the analysis of non-conforming production in terms of the development of retained units for evaluation by the quality department and in terms of the development of scrap in a company involved in the production of tubes for the automotive and energy industries. The bottlenecks in the production process have been investigated and analysed, and the necessary measures have subsequently been determined. A new perspective on the issue of mismatched production was obtained, and new solutions were found that helped the company improve the efficiency of its production processes and thus increase its competitiveness. The analyses of non-conforming production presented in the paper are applicable in many enterprises. When the efficiency of production is increased, unnecessary losses are avoided. This will satisfy the philosophy of lean manufacturing, which aims to produce products in the shortest possible time with minimal cost.
Design of the production technology of a bent component
(MDPI, 2023) Čada, Radek; Pektor, Tomáš
This paper concerns the design of the technology for the production of the part by bending and also the design of the forming tool for a small number of pieces of the produced part. The part in question was the oscillating tool blade to cut soft materials. The aim was to design economically advantageous technology to produce this blade without spot welding from two parts, preferably from one semi-finished product. A suitable material for the part and its new shape were designed. Calculations were made for the smallest recommended internal bending radius, the largest allowable bending radius, the smallest length of the bending arm, and the angle of springback after bending. The component’s shape and a suitable blank were determined. A low-cost bending tool was designed. Dynaform simulations were used to analyse deformation, material thickness after bending, and formability. Analyses showed that the designed bending manufacturing process is safe. The bending tool and then the cutting blade test pieces were produced to verify the tool’s functionality. The procedure for designing the manufacturing process and the forming tool presented in the paper can be applied in cases where it is necessary to design a suitable technology to produce a small number of parts by forming to achieve a minimum cost per piece of the manufactured part.
Investigation of the effects of various severe plastic deformation techniques on the microstructure of laser powder bed fusion AlSi10Mg alloy
(MDPI, 2023) Snopiński, Przemysław; Matus, Krzysztof; Hilšer, Ondřej
In this paper, we present a complete characterization of the microstructural changes that occur in an LPBF AlSi10Mg alloy subjected to various post-processing methods, including equal channel angular pressing (ECAP), KoBo extrusion, and multi-axial forging. Kikuchi transmission diffraction and transmission electron microscopy were used to examine the microstructures. Our findings revealed that multi-axis forging produced an extremely fine subgrain structure. KoBo extrusion resulted in a practically dislocation-free microstructure. ECAP processing at temperatures between 100 ◦C and 200 ◦C generated moderate grain refinement, with subgrain diameters averaging from 300 nm to 700 nm. The obtained data highlighted the potential of severe plastic deformation as a versatile method for tailoring the microstructure of the AlSi10Mg alloy. The ability to precisely control grain size and dislocation density using specific SPD methods allows for the development of novel materials with ultrafine-grained microstructures that offer the potential for enhanced mechanical and functional properties.
Revealing the strengthening contribution of stacking faults, dislocations and grain boundaries in severely deformed LPBF AlSi10Mg alloy
(Springer Nature, 2023) Snopiński, Przemysław; Kotoul, Michal; Petruška, Jindřich; Rusz, Stanislav; Żaba, Krzysztof; Hilšer, Ondřej
In this study, microstructural features direct metal laser melted (DMLM) aluminium–silicon magnesium (AlSi10Mg) are investigated using advanced transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). The focus is on post-processing by ECAP (Equal Channel Angular Pressing) and its efects on grain refnement, stacking fault formation and dislocation accumulation. In addition, the strength enhancing role of stacking faults is for the frst time quantifed. The results show that ECAP can increase the yield strength from 294 to 396 MPa, while the elongation increases from 2.4% to 6%. These results show that ECAP processing ofers a new approach for producing AlSi10Mg products with improved strength and ductility.
A study on two-warehouse inventory systems with integrated multi-purpose production unit and partitioned rental warehouse
(MDPI, 2023) Viswanath, Jagadeesan; Thilagavathi, Rajamanickam; Schindlerová, Vladimíra; Subbarayan, Sreelakshmi; Čep, Robert
A study of two warehouse inventory systems with a production unit is developed in this article with some constraints which are of practical applicability to optimize the total production cycle and its cost. A production unit evolves in three different states to retain its quality and prolong its lifetime: the state of producing items, the state of reworking the identified defective items, and the state of being idle. It processes the items up to a certain time point. The screening process starts immediately after a product comes out of the production unit. The classified non-defective items are first stored in own warehouse (OW), after filling to its maximum capacity, and the remaining items fill in the first block (RW1) of the rental warehouse (RW). All identified defective items are stored in the second block (RW2) of RW. The holding cost of an item is higher in RW than OW. All defective items are sent to the production unit for re-do processes as a single lot immediately after the stop of the production and re-do items are stored in RW1 to satisfy the demand. The items in the RW1 are of higher priority in satisfying the demands after the stop of the production unit in producing new items as to deduce the total cost. Demand is assumed as both time and advertisement dependent and is encouraged once production starts. The deterioration rate differs in both warehouses. No backlog is entertained. The study is directed to achieve optimum total cycle cost towards the attainment of the optimum production time slot and the entire cycle of the system. We have arrived at explicit expressions for the total cost function of the entire production cycle. An analytic optimization process of the discriminant method is employed in the form of an algorithm to arrive at the optimum total cost. It provides a numerical illustration of a specific environment. The implications of the current research work are as follows. The optimum utility of production units in three different states in arriving at the optimum total cost is extensively studied with respect to deterioration, demand, and production rates. It also examined the influence of fluctuating deterioration, demand, and production parameters in arriving at optimum deterioration cost, holding cost, and total cycle cost, as they have important managerial insights. The effect of rental charges on the optimum total cost is examined as the system is used for multi-purpose storage.
Effect of ECAP process on deformability, microstructure and conductivity of CuCoNi alloy
(Technical Faculty, Bor, 2023) Grzegorczyk, B.; Rusz, Stanislav; Snopiński, P.; Hilšer, Ondřej; Skowronek, A.; Grajcar, A.
The study deals with the influence of various variants of severe plastic deformation in the Equal Channel Angular Pressing (ECAP) process on the microstructure, microhardness, and conductivity of CuCoNi alloy. The microstructure evolution was studied by microscopic observations and electron back-scattered diffraction (EBSD) in a scanning electron microscope (SEM). The Vickers method was used to test the microhardness of the samples after various variants of the ECAP process. The conductivity was measured with an eddy current electrical conductivity meter based on the complex impedance of the probe. The results indicated the possibility of deformation of CuCoNi alloys in the process of pressing through the ECAP angular channel and developing their microstructure and properties. The method is an effective tool for strengthening the tested copper alloy by refining its microstructure. After the first pass, the grain size was reduced by 80%. Increasing the plastic deformation temperature did not significantly affect the obtained level of microstructure fragmentation - the average grain size is approx. 1.4-1.5 μm. The fragmentation of the microstructure had a negligible effect on the conductivity of the CuCoNi alloy, which oscillated at the value of 13 MS/m after the ECAP process.
Effects of built direction and deformation temperature on the grain refinement of 3D printed AlSi10Mg alloy processed by equal channel angular pressing (ECAP)
(MDPI, 2023) Snopiński, Przemysław; Matus, Krzysztof; Hilšer, Ondřej; Rusz, Stanislav
In this work, we used an AlSi10Mg alloy produced by selective laser melting (SLM) to study the effects of build direction and deformation temperature on the grain refinement process. Two different build orientations of 0◦ and 90◦ and deformation temperatures of 150 ◦C and 200 ◦C were selected to study this effect. Light microscopy, electron backscatter diffraction and transmission electron microscopy were used to investigate the microtexture and microstructural evolution of the laser powder bed fusion (LPBF) billets. Grain boundary maps showed that the proportion of low angle grain boundaries (LAGBs) dominated in every analysed sample. It was also found that different thermal histories caused by the change in build direction resulted in microstructures with different grain sizes. In addition, EBSD maps revealed heterogeneous microstructures comprising equiaxed fine-grained zones with ≈0.6 µm grain size and coarse-grained zones with ≈10 µm grain size. From the detailed microstructural observations, it was found that the formation of a heterogeneous microstructure is closely related to the increased fraction of melt pool borders. The results presented in this article confirm that the build direction has a significant influence on the microstructure evolution during the ECAP process.
Tuning the defects density in additively manufactured fcc aluminium alloy via modifying the cellular structure and post-processing deformation
(Elsevier, 2023) Snopiński, Przemysław; Hilšer, Ondřej; Hajnyš, Jiří
In this study, using an L-PBF AlSi10Mg alloy with different microstructural properties, the typical structural defects caused by severe plastic deformation are investigated by scanning electron microscopy and high-resolution transmission electron microscopy. Microscopic characterization shows that the deformed L-PBF AlSi10Mg alloy exhibits a heterogeneous microstructure consisting of Al/Si interfaces and a high density of dislocations, stacking faults, and nanotwins. On the basis of experimental data, it is also shown that high stresses build up at the Al/Si interface due to incompatible deformation, enabling the activation of novel deformation modes that control the plastic deformation of the hard Si twin phase and amorphization in the solid state. The revealed synergy and novel deformation modes open a new horizon for the development of next-generation structural materials and provide insights into the atomically resolved structures of dislocations and GBs in nanostructured L-PBF alloys.
Finite element analysis of twist channel angular pressing
(MM Science, 2023) Hilšer, Ondřej; Pastrňák, Martin; Rusz, Stanislav; Krupová, Hana; Snopiński, Przemysław
The article deals with the analysis of the unconventional pressing process of metallic materials by twist channel angular pressing (TCAP) method. TCAP process is a modification of the equal channel angular pressing (ECAP) forming method, which can be used to prepare bulk materials with an ultra fine-grained structure. Simulation of the TCAP process is an important source of information on the effect of design and technological parameters on the grain refinement efficiency. The TCAP process was simulated using 3D finite element method (FEM).
Simulation and optimisation of the assembly line production process
(MM Science, 2023) Schindlerová, Vladimíra; Šajdlerová, Ivana; Bučko, Michal; Klepková, Lucie
Optimisations in production processes are routine in most engineering companies. The possibility of using simulation is crucial for the industry in the 21st century because it provides an opportunity to verify many variants in a very short time. The results obtained in this way can then contribute to faster decision-making in the field of manufacturing process optimisation. The paper includes a case study of the assembly line production process. The aim was to find bottlenecks in the product production process and capture and propose improvements not only in the technical but also in the production and ergonomic area. A "virtual twin " of the given process was also created in the Witness simulation program with the possibility to analyse and verify proposals for the work activities redistribution of assembly station operators.
Microstructure evolution of AZ31 magnesium alloy during twist channel angular pressing
(MM Science, 2023) Pastrňák, Martin; Rusz, Stanislav; Hilšer, Ondřej
Microstructure evolution of hot extruded AZ31 magnesium alloy during twist channel angular pressing was investigated. The grains were refined significantly after one to four passes at 200°C. Microstructure evolution after TCAP processing was investigated using optical microscopy, transmission electron microscopy and electron backscatter diffraction. The results show effect of TCAP process on the achieving the UFG structure with average grain size below 1 μm.

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