Papers by Zbigniew Siemiątkowski
Reasonable efforts have been made to publish reliable data and information, but the author and pu... more Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. The Open Access version of this book, available at www.taylorfrancis.com, has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license. The Open Access option was financed by Polish Ministry of Education and Science in the frame of program 'Excellent Science' project No. DNM/SP/512333/2021 titled Monografia Remanufacturing and Advanced Machining Processes for New Materials and Components in amount 63,649.92 zł.
Engineering for Rural Development, May 24, 2023
The research was performed in the context of feasibility examinations of chromia application as c... more The research was performed in the context of feasibility examinations of chromia application as cutting tool materials. In the paper, a study on the Cr2O3-based ceramic cutting tools is presented from the perspective of structural features and durability under various machining parameters. Comparative analysis was performed using alumina-based ceramic cutting inserts. Microstructure was examined using scanning and transmission electron microscopy (SEM and TEM), LEO1455 VP (ZEISS) and MIRA3 TESCAN, respectively. It was found that Cr2O3-based ceramic with AlN additions after electroconsolidation exhibited more fine structure with evenly distributed AlN inclusions and small amount of spherical pores, below 2%. The cutting durability tests were performed with both hardened NC11LV and non-hardened C45 (1.0503) steels, using multiedge cutting inserts of dimensions 14.75 mm × 14.75 mm × 4.75 mm, made of respective ceramics. The machine tool Mazak QTE was used for the tests, and the wear criterion was 0.4 mm notch wear value, assessed with Keyence microscope. It was demonstrated that a pure alumina cutting tool exhibited 3 times larger wear than Cr2O3-AlN one after 25 minutes of work. On the other hand, Cr2O3-AlN cutting edge reached the same wear rate at 175 m•min-1 as Al2O3-based tools at just 50 m•min-1. For the same cutting speed of 150 m•min-1 , the chromia-based ceramic insert worked over 30 minutes, two times longer than alumina ones. The increased wear resistance and durability can be attributed to the finedispersed structure obtained not only by certain proportion of components, but also by the electroconsolidation technique with specific parameters.
Machines
The paper is dedicated to the enhancement of Polycrystalline Diamond Bits (PDC) designed for oil ... more The paper is dedicated to the enhancement of Polycrystalline Diamond Bits (PDC) designed for oil and gas industry. A novel diamond-reinforced composite was applied for cutting inserts, with the addition of 4 wt% chromium diboride to the WC-Co matrix. The addition of CrB2 ensured improvement of bending strength and fracture toughness by nearly 30% and 40%, respectively, and enhanced the diamond retention force. The efficiency of PDC bits was further improved by incorporating constructional features in both bottomhole and reaming parts. An analytical relationship between the feeding speed and geometrical parameters was found, including the wings and calibrating inserts numbers, as well as the rotational speed of the cutter. Under the conditions of rock fracture by reaming inserts, the approximate value of the required power was calculated.
Advances in Science and Technology Research Journal
The paper presents research results on the enhancement of diamond composites designed for tools a... more The paper presents research results on the enhancement of diamond composites designed for tools application for mining industry, hard rocks cutting, able to withstand harsh conditions under heavy dynamical loads. In the present study, both CrB 2 micropowder and VN nanopowder additives were used in proportions up to 5 wt.% and 6 wt.%, respectively, together with the basic matrix composition of 51 wt.% Fe, 32 wt.% Cu, 9 wt.% Ni, and 8 wt.% Sn. Addition of both components, CrB 2 and VN, appeared to be advantageous in proportion of 2 wt.% and 4 wt.%, respectively. This composition exhibited the highest relative density of 0.9968, better than that without additives. Similarly, the highest values of compressive strength R cm and flexural strength R bm were reached for the composite with the same percentage of CrB 2 and VN. Compared to the composite with no addition of CrB 2 and VN, R cm improved by almost 70%, while R bm by 81%. Additionally, the abovementioned additives enhanced the ability of the matrix to prevent the diamond reinforcement from being torn out of the composite, which is very important under harsh working conditions of the cutting tools. The presence of CrB 2 micropowder and VN nanopowder promoted densification of the matrix and adhesion between the diamond grits and the Fe-Cu-Ni-Sn matrix.
DEStech Transactions on Computer Science and Engineering, 2019
The paper presents theoretical and experimental results in the field of the manufacturing of ceme... more The paper presents theoretical and experimental results in the field of the manufacturing of cemented tungsten carbide materials. The important issue of avoiding any additional substances like plasticizers was challenged in order to reach the maximal possible density of sintered material while keeping its purity. To solve the problem, the electroconsolidation method of hot pressing supported by direct current was applied. The respective apparatus was constructed that enabled WC nanopowders to be sintered under pressure and high temperature during a very short time of ca. 3 minutes. In the experiments, because of the short heating time, grain size of the sintered bulk WC increased insignificantly, in general, remaining smaller than 1 μm. Similarly, sintering under hot pressing with direct current, a mixture of 3% by weight Y 2 O 3 stabilized ZrO 2 and 50% by weight WC, produced a fine structure with a uniformly distributed WC grains. The applied electric field led to the formation of a temperature gradient around the pores, with a favourable impact on the compaction of large pores and an increase in the final density of the bulk material. The experimental research confirmed that the main mechanism of the densification of nanodispersed powders of tungsten monocarbide was a locally inhomogeneous diffusion-viscous flow with intergranular slipping.
Metals and Materials International, 2018
A comprehensive characterization of the near surface formed during the interrupted high-speed dry... more A comprehensive characterization of the near surface formed during the interrupted high-speed dry ceramic milling of IN718 was performed using light imaging, SEM/EDX, TEM and nano-hardness methods. It was found out that even an initial cut by a fresh tool creates a sub-surface alteration roughly 20 µm deep. The depth of altered sub-surface progressively changed to a roughly 40 µm when the tool reached an approximately half of its life, and almost 60 µm at the tool's end of the life. In the last two cases, the visible WEL (utilizing a light microscope) of the thickness roughly 6 and 15 µm was created, respectively. The outermost layer of the deformed subsurface was found to be for all three cases approximately 1.5 µm thick and composed of dynamically recrystallized γ phase grains with the average diameter of approximately 150 nm. This layer was free of δ phase and γ′ or γ″ precipitates. It was followed by a plastically deformed zone.
Remanufacturing and Advanced Machining Processes for New Materials and Components, 2022
Lecture Notes in Mechanical Engineering, 2017
The paper describes investigation results aimed to the assessment of the shrink-fitting of the ma... more The paper describes investigation results aimed to the assessment of the shrink-fitting of the marine diesel crankshaft elements. Since the crankshafts are of the large size (above 20 m) and weight (above 300 tons), the models were made in scale 1:5, keeping the same technical conditions. The measurement of internal stresses was made by a non-destructive ultrasonic method. The obtained results confirmed the existence of the zones where stresses had crossed the yield points, which meant the plastic deformation and weakening of the interference fit.
International Journal of Refractory Metals and Hard Materials, 2017
The paper presents the preliminary results of investigations on hot pressure sintering under the ... more The paper presents the preliminary results of investigations on hot pressure sintering under the alternating current. The aluminium oxide Al 2 O 3 and tungsten monocarbide WC powders of submicron grain sizes were used to obtain the sintered structure at various temperatures, pressures, current and other physical conditions. The analysis of the physical properties of obtained ceramics revealed increased hardness and even some elasticity and substantially increased flexural strength. Out of the nanostructured mixture of Al 2 O 3 and WC powders in proportion 50-50%, the inserts for cutting tools were made. The comparative analysis of those inserts with the ones typically available in the market confirmed increased durability (up to 30%), as it had been expected. The obtained structure could be further improved, and if the grains in the sintered material become smaller than 1 μm, even better physical properties, wear-resistance and durability could be expected.
DEStech Transactions on Computer Science and Engineering, 2019
The paper presents an investigation of results on an additive manufactured drill base body. Due t... more The paper presents an investigation of results on an additive manufactured drill base body. Due to the technological and strength limitations, conventional drills with inner coolant ducts may not be smaller than 13 mm diameter. The novel idea was to keep the strength of small diameter drills making spiral coolant ducts. Drills were fabricated using a 3D laser printer to obtain the designed geometry in a way not affecting its stiffness and strength. The tensile strength of samples was between R m = 1287 and 1603 MPa, and microhardness of drills was between 606 and 627 HV5. The sintered material revealed a very small porosity rate (below 1%) and very few discontinuities. Thus, it was demonstrated that the 3D laser printing enabled the production of advantageous drill base bodies.
Facta Universitatis, Series: Mechanical Engineering
In the paper, the issue of the supervision of belt tension and wear in industrial feeder is addre... more In the paper, the issue of the supervision of belt tension and wear in industrial feeder is addressed. The designed system is based on strain gauges that are built into the roller and are subject to the belt pressure at each revolution. In order to assess the effectiveness of this system, calibration and uncertainty analysis was performed. As a result, it was demonstrated that the main source of uncertainty was the function of approximation, while the others were orders of magnitude smaller. The final function provided results with accuracy of ca. 10% of actually measured value, which was assumed to be a good result for this particular industrial application.
Remanufacturing and Advanced Machining Processes for New Materials and Components, 2022
Remanufacturing and Advanced Machining Processes for New Materials and Components, 2022
Archive of Mechanical Engineering, 2006
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Papers by Zbigniew Siemiątkowski