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1

Numerical analysis of the cavitation effect occurring on the surface of steel constructional elements

Linek T., Tański T., Borek W.

Archives of Materials Science and Engineering

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2017

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Vol. 85, nr 1

24--34

EN

Purpose: The aim of the work is to present the results of own investigations concerning the geometric optimisation of constructional elements working in the environment of cavitation wear together with a computer numerical analysis. The engineering material used for constructional elements working in the environment of cavitation wear is steel, commonly used for pressure devices working at elevated temperatures, P265GH, acc. to PN-EN 10028:2010. Design/methodology/approach: SOLID EDGE ST 7 software, for synchronous designing, was used for the parametrisation of the shape, distribution, configuration and size of openings in constructional elements. Five models, with a different spacing and number of openings, were proposed for the optimisation of internal geometry of the cavitation generator and for the investigations; the models were then subjected to a numerical analysis using specialised software, ANSYS FLUENT v.16, employed for modelling the effects associated with fluid mechanics (Computational Fluid Dynamics - CFD). The data was implemented for this purpose in the software used, such as: density, yield point, tensile strength, heat conductivity coefficient for steel P265GH, material surface roughness, medium (water) flow rate, constant pressure loss of medium, pressure of steam saturation in a medium; and such data was called boundary conditions. Findings: The authors’ principal accomplishment is the optimisation of the shape, the selection of the most appropriate geometry of a constructional element generating the maximum number of cavity implosions in the environment of a flowing medium (water), with the use of computer tools dedicated to engineering design: a 3D and numerical computer analysis of fluid mechanics, CFD. Moreover, an attempt was made in this work to develop a methodology for characterisation of the phenomena accompanying the environment of cavitation wear. Practical implications: A possibility of examining the phenomena and a process of wear of a constructional element made of P265GH grade steel for pressure devices working at elevated temperatures. The demonstration and presentation of potential places, areas and sizes of erosion existing on constructional elements working in the environment of cavitation wear.

2

Precipitation evolution and surface modification of magnesium alloys

Tański T., Król M., Dobrzański L.A., Malara S., Domagała-Dubiel J.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

87--149

EN

Purpose: The purpose of this publication is to present the results of own long-term research summarising the experience concerning as casting magnesium alloys, and in especially a thermal analysis describing the process of alloys crystallisation, standard heat treatment according to the occurring phase transitions and precipitation processes, surface treatment with the CVD and PVD methods, laser surface treatment of surface layers, as well as using the methods of Computer Materials Science. Design/methodology/approach: The research concerned in the first place an analysis of Mg-Al-Zn alloys crystallisation kinetics. Optimisation investigations for heat treatment conditions taking into consideration different cooling mediums were performed in order to identify fully the structure of the investigated magnesium casting alloys. Investigations were carried out of the structure and properties of coatings produced with the CVD and PVD methods on the investigated Mg-Al-Zn alloys. The last stage of investigating the presented Mg-Al-Zn alloys applied to laser surface treatment enabling to produce a quasi-composite structure of MMCs characterised by the gradient of phase composition as well as functional properties by feeding hard ceramic particles, in particular carbides and oxides, into the surface of the materials produced. Findings: Valuable and original results were achieved based on the broad scope of the research performed both, in cognitive and applicational terms, concentrated mainly on the analysis and influence of chemical composition and technological heat and surface treatment processes on the structure and properties of the investigated alloys. Practical implications: The properties of the core and surface layer of the part produced can be customised most advantageously by selecting the part’s material and its structure and properties formation processes appropriately along with the surface layer type and technology ensuring the required functional properties. Originality/value: The knowledge gathered for years concerning light metal alloys, and in particular Mg-Al-Zn alloys, of an undoubtedly valuable cognitive character, is dedicated not only to students but also postgraduates and researches to improve the conditions of education.

3

Computer simulation of stresses in coatings obtained in the PVD process

Śliwa A., Kwaśny W., Dobrzański L. A.

Inżynieria Materiałowa

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2010

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Vol. 31, nr 3

732-734

EN

The paper presents application of the Finite Element Method for determining the internal stresses occurring in the Ti+Ti(Al,N) coatings obtained in the magnetron PVD process on the PM HS6-5-3-8 type sintered high-speed steel. The model was developed using FEM, relevant for the investigated test pieces, for the computer simulation of the internal stresses in coatings, which was verified experimentally by comparing the calculation results with the experimental results.

PL

W pracy przedstawiono zastosowanie metody elementów skończonych do wyznaczania naprężeń własnych występujących w powłokach Ti + Ti- (Al, N), uzyskanych w magnetronowym procesie PVD na spiekanej stali szybkotnącej PM HS6-5-3-8. Dla celów symulacji komputerowej naprężeń własnych w powłokach z wykorzystaniem MES opracowano odpowiedni dla analizowanych próbek model, który poddano weryfikacji doświadczalnej, dokonując porównania wyników obliczeń z wynikami badań eksperymentalnych.

4

The computer simulation of stresses in the Ti+TiC coatings obtained in the PVD process

Dobrzański L. A., Śliwa A., Kwaśny W., Sitek W.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

241--244

EN

Purpose: The aim of the research is the computer simulation of the internal stresses in bilayer coatings Ti+TiC obtained in the magnetron PVD process on the ASP 30 sintered high-speed steel. Design/methodology/approach: Computer simulation of stresses was carried out in ANSYS environment, using the FEM method and the experimental values of stresses were determined basing on the X-ray diffraction patterns. Findings: The computer simulation results correlate with the experimental results. The presented model meets the initial criteria, which gives ground to the assumption about its usability for determining the stresses in coatings, employing the finite element method using the ANSYS program. Research limitations/implications: In order to evaluate with more detail the possibility of applying these coatings in tools, further computer simulation should be concentrated on the determination of other properties of the coatings for example- microhardness. Originality/value: Presently the computer simulation is very popular and it is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution. The possibility of application faster and faster calculation machines and coming into being many software make possible the creation of more precise models and more adequate ones to reality.

5

Zastosowanie metod sztucznej inteligencji do predykcji własności produktów hutniczych ze stali konstrukcyjnych

Dobrzański L. A., Kowalski M., Madejski J.

Hutnik, Wiadomości Hutnicze

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2005

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Vol. 72, nr 3

155--162

PL

W pracy opisano sposób predykcji wytrzymałości na rozciąganie oraz granicy plastyczności stali, z wykorzystaniem narzędzi sztucznej inteligencji. Opracowane modele wykorzystujące sztuczne sieci neuronowe wykorzystano następnie do opracowania symulatora, pozwalającego na obserwację analizowanych własności stali, przy ciągłej zmianie składu chemicznego oraz parametrów technologicznych produkcji stali. Wykorzystano również algorytmy genetyczne dla doboru składu chemicznego stali zapewniającego minimalizację ryzyka wytwarzania produktów nie spełniających założonych wymagań.

EN

The paper presents the new method for forecasting the yield point and the ultimate tensile strength for steel using the artificial intelligence tools. The developed models, using the artificial neural networks were used next for developing the simulator making itpossible to visualise the analysed properties of steel at the continuous changes ofits chemical composition and technological parameters of steel production. Genetic algorithms were also used for selection of the steel chemical composition, ensuring minimisation ofthe risk of manufacturing products that would not meet the requirements.