Wyniki wyszukiwania - Biblioteka Nauki

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

100%

Linek T. , Tański T. , Borek W.

Archives of Materials Science and Engineering

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2017

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tom 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

PVD surface treatment of heat-treated cast aluminium alloys

88%

Tański T. , Dobrzański L. A. , Wiśniowski M. , Linek T. , Szklarek R.

Archives of Materials Science and Engineering

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2016

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tom Vol. 79, nr 2

79--88

EN

Purpose: Main purpose of the paper is results share of AlSi9Cu and AlSi9Cu4 cast aluminium alloys treatment investigation. Processing was performed using CAE-PVD method in order to obtain gradient coatings. Design/methodology/approach: CAE-PVD method was used to obtain gradient coatings on AlSi9Cu and AlSi9Cu4 cast aluminium alloys after heat treatment. Investigation of resulting material was performed using SEM, TEM, GDOS, ball-on-disk wear resistance test and microhardness test. Findings: The investigations presented in this paper reveal that it was possible to successfully deposit Cr/CrN/CrN, Cr/CrN/TiN, and Ti/Ti(C,N)/(Ti,Al)N nano-crystalline coatings on Al-Si-Cu aluminium substrate using CAE-PVD method. Investigations of the coatings reveal a microstructure that adhere tightly to the aluminium substrate without any visible delamination but with visible transition zone between the investigated layers and the substrate material. Research limitations/implications: There is need for further research activity in field of nanocomposite films and coatings that should concentrate on following problems: controlled grain size of coatings/films, development of hybrid coatings with unique physical and functional properties, e.g. nanophase biomaterials. Practical implications: Better understanding of mechanisms that proceed during CAE-PVD treatment of AlSi9Cu and AlSi9Cu4 cast aluminium alloys. Creation of material, that, thanks to the treatment, can be coated with layer characterized by gradient chemical composition with unique physical and functional properties (e.g. higher microhardness or corrosion resistance, lower friction coefficient, etc.) that can be successfully applied within aerospace and automotive industry or even on field of biomedical applications with use of nanophase biomaterials or nano-crystalline amorphous materials. Originality/value: Cr/CrN/CrN, Cr/CrN/TiN, and Ti/Ti(C,N)/(Ti,Al)N nano-crystalline coatings were deposited on Al-Si-Cu aluminium substrate. They are characterized by visible transition zone (gradient) between the investigated layers and the substrate material.

3

The evaluation of suitability for operation of repair low-alloy steel welded joints

75%

Dziuba-Kałuża M. , Zieliński A. , Jasiński A. , Sroka M. , Dobrzański J. , Linek T.

Archives of Materials Science and Engineering

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2016

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tom Vol. 78, nr 2

78--86

EN

Purpose: The purpose of the work was to evaluate the material condition of repair welded joints of steam pipelines with regard to their suitability for operation including determination of the time of their further safe operation. Design/methodology/approach: The following was carried out: microstructure investigations using scanning electron microscopy, investigations on mechanical properties at room and elevated temperatures, determination of the fracture appearance transition temperature based on impact tests. The abridged creep tests without measurement of elongation during test were carried out to determine the material’s residual life. Findings: The time of safe operation was determined for welded joints made in 14MoV63 steel after long-term service and 14MoV63 steel after long-term service and in the as-received condition. Practical implications: The applied methodology and the adopted procedures are used in evaluating the condition and forecasting further operation of new repair welded joints for the pressure part components of power equipment working under creep conditions. Originality/value: The obtained results of investigations will be the elements of materials characteristics worked out by the Institute for Ferrous Metallurgy for the steels and welded joints made in them to work under creep conditions.

4

Influence of processing routes on structure and residual stress in aluminium-magnesium alloy after ECAP

75%

Tański T. , Snopiński P. , Nuckowski P. , Jung T. , Kwaśny W. , Linek T.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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tom Vol. 63, nr 1

5--12

EN

Purpose: The main goal of present study is try to find the influence of severe plastic deformation using the ECAP (equal channel angular pressing) process and different processing routes on structure formation, properties and lattice strain of EN AC 51100 alloy. Design/methodology/approach: The cold ECAP behaviour was determined using three different processing routes A, Bc and C and four repetitive pressings. The comparison between three types of processing routes has been established based on microstructure observation, grain size measurements and X-ray diffraction analysis. Findings: It was found that the structure after three types of mechanical treatments is strongly deformed, and the processing route has a significant impact on shape and grain size. It was also found that direction of shearing patterns that appears after deformation have influence on residual stress in ECAPed material. The use of equal channel angular pressing method has also an influence on hardness of investigated alloy which increase more than 90% after four repetitive pressings. Research limitations/implications: Current study presents the investigation results which was carried out on samples, not on final products. Practical implications: Current research is moving towards to develop high strength materials with increased mechanical properties and fine microstructure which are known as ultra-fine-grained materials, compared to well-known common materials. Originality/value: This paper presents the results of structure and properties investigation including X-ray analysis of severely deformed AlMg3 alloy by ECAP process.