Wyniki wyszukiwania - Biblioteka Nauki

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Effect of hot deformation and isothermal holding temperature on retained austenite characteristics in 3-5% Mn multiphase steels

100%

Opiela M. , Grajcar A. , Pakieła W.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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tom Vol. 71, nr 2

art. no. e144611

EN

The paper presents stress-strain characteristics recorded during the four-step compression of axisymmetric samples in the Gleeble thermomechanical simulator. The hot deformability of three steels with Mn concentrations of 3%, 4% and 5% was compared. The analysis of the influence of plastic deformation and Mn content on the microstructure of alloys, and in particular, on a fraction and morphological features of the retained austenite, was performed. The proportion of the retained austenite was determined by the X-ray diffraction method. It was found that the content of Mn in the range from 3% to 5% does not have a significant impact on the high-temperature resistance of the steel during compression tests, but it has a significant influence on the microstructure of the steel and the fraction of retained austenite. The optimal conditions for maximizing the proportion of retained austenite were obtained at the temperature of 400 °C, and it decreased with increasing Mn concentration in the steel. It has been shown that it is related to the redistribution of carbon from the remaining austenite fraction with an increase in the manganese content. The mechanical properties were determined on the basis of hardness measurements.

2

Laser welding of ferritic stainless steel 1.4509 used in the manufacturing of catalyst housings and diesel particulate filters

88%

Lisiecki A. , Rokita Z. , Ginalski D. , Kośny A. , Pakieła W.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2022

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tom Vol. 66, No. 3

7--17

EN

The article discusses the results of tests as well as quality assessments of test joints made of tubes having a nominal thickness of 1.5 mm, a rectangular cross-section and a width of 140 mm and a length of 240 mm, made of ferritic stainless steel grade 1.4509 with the addition of microagents and used in the production of catalyst housings and diesel particulate filters. Test joints were made using a prototype line equipped with a TruDisk 2002 disk laser (TRUMPF) at a ROCH production plant in Tarnowskie Góry. The tests involved the preparation of an experimental batch of tubes. The tubes used in the tests were subjected to various procedures, i.e. only to laser welding (5 specimens), to the rolling of the weld surface after laser welding (5 specimens) and to the additional heat treatment of the joint area after welding (5 specimens). Most of the test welded joints represented high quality level B and were characterised by tensile strength not lower than that of the base material as well as by high plasticity confirmed in the Erichsen cupping test. However, slight undercuts of the weld root revealed in the tests indicated the risk of the partial lack of penetration or the formation of excessive undercuts in the production process. The foregoing necessitates the strict application of the welding procedure and, in particular, the ensuring of the high precision of laser beam positioning and accuracy when preparing sheet edges before welding.

PL

W artykule opisano wyniki badań i oceny jakości złączy próbnych rur o grubości nominalnej 1,5 mm, przekroju prostokątnym i szerokości 140 mm oraz długości 240 mm ze stali nierdzewnej ferrytycznej z mikrododatkami gatunku 1.4509, przeznaczonych do wytwarzania obudów katalizatorów i filtrów cząstek stałych. Złącza próbne wykonano za pomocą prototypowej linii z laserem dyskowym TRUMPF TruDisk 2002 w zakładzie produkcyjnym ROCH w Tarnowskich Górach. Do badań przygotowano partię doświadczalną rur bezpośrednio po spawaniu laserowym, z rozwalcowaną powierzchnią spoiny oraz po dodatkowej obróbce cieplnej obszaru złącza. Większość badanych złączy próbnych charakteryzuje się wysokim poziomem jakości B, wytrzymałością na rozciąganie nie niższą od materiału rodzimego oraz wysoką plastycznością, potwierdzoną w próbie tłoczności. Jednak ujawnione nieznaczne podtopienia grani spoiny wskazują na ryzyko wystąpienia częściowego braku przetopienia lub nadmiernych podtopień w procesie produkcyjnym. Z tego względu konieczne jest ścisłe stosowanie procedury spawania, w szczególności zapewnienie wysokiej precyzji pozycjonowania wiązki laserowej oraz dokładności przygotowania krawędzi blach do spawania.

3

Copper Beam Electron Alloying with Ti Powder

88%

Smolarczyk P. , Krupiński M. , Węglowski M. , Pakieła W. , Śliwiński P.

Archives of Foundry Engineering

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2024

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tom Vol. 24, iss. 1

88--93

EN

The paper presents the effect of electron beam alloying on the surface of a copper flat bar (M1Ez4) with titanium powder. Due to the quality of the surface after alloying and the obtained properties, the parameters used were given which met the assumed conditions to the greatest extent. The microstructure and mechanical properties as well as the chemical composition of surface-modified electron-beam copper show improved mechanical properties, i.e. hardness and abrasion resistance. This article uses research techniques using scanning electron microscopy and analysis of chemical composition in micro-areas (EDS). In order to examine the properties of the material after electron beam modification, hardness measurements were performed at low loads (HV0.1), abrasion resistance was tested, and conductivity was also measured. As a result of modifying the chemical and phase composition of M1E copper using an electron beam, the hardness increased by 46%, while the conductivity decreased by 16% due to the formation of intermetallic phases during solidification.

4

Mechanical alloying of Mg-Zn-Ca-Er alloy

88%

Hrapkowicz B. , Lesz S. , Kremzer M. , Karolus M. , Pakieła W.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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tom Vol. 69, nr 5

art. no. e137587

EN

Magnesium-based materials constitute promising alternatives for medical applications, due to their characteristics, such as good mechanical and biological properties. This opens many possibilities for biodegradable materials to be used as less-invasive options for treatment. Degradation is prompted by their chemical composition and microstructure. Both those aspects can be finely adjusted by means of proper manufacturing processes, such as mechanical alloying (MA). Furthermore, MA allows for alloying elements that would normally be really hard to mix due to their very different properties. Magnesium usually needs various alloying elements, which can further increase its characteristics. Alloying magnesium with rare earth elements is considered to greatly improve the aforementioned properties. Due to that fact, erbium was used as one of the alloying elements, alongside zinc and calcium, to obtain an Mg₆₄Zn₃₀Ca₄Er₁ alloy via mechanical alloying. The alloy was milled in the SPEX 8000 Dual Mixer/Mill high energy mill under an argon atmosphere for 8, 13, and 20 hours. It was assessed using X-ray diffraction, energy dispersive spectroscopy and granulometric analysis as well as by studying its hardness. The hardness values reached 232, 250, and 302 HV, respectively, which is closely related to their particle size. Average particle sizes were 15, 16, and 17 μm, respectively.

5

Dekarbonizacja metanu z udziałem katalizatorów na bazie żelaza

75%

Wojtasik M. , Żak G. , Markowski J. , Burnus Z. , Krasodomski W. , Pakieła W.

Przemysł Chemiczny

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2023

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tom T. 102, nr 3

259--263

PL

Zbadano wpływ dwóch prostych, łatwo dostępnych i tanich katalizatorów żelazowych, tlenku żelaza i wiórków stalowych. Dla procesów katalitycznych oraz porównawczo dla procesu termicznego zbadano składy gazów poprocesowych w temp. 600, 750, 850, 950C i 1050°C. W gazach poprocesowych oznaczono zawartość metanu, wodoru, azotu, tlenu i sumy węglowodorów C₂ i C₃ za pomocą GC. Dla poszczególnych procesów wyznaczono konwersję metanu. Węgiel powstający w procesie zobrazowano metodą SEM i EDS i oceniono stopień jego grafityzacji za pomocą spektroskopii Ramana.

EN

MeH was thermally or catalytically pyrolyzed in the presence of Fe₂O₃ or steel shavings at temp. of 600, 750, 850, 950 and 1050°C. In the post-process gases, the content of MeH, H₂, N₂, O₂ and the sum of C₂ and C₃ hydrocarbons were detd. by GC and the conversion of MeH was calculated. The C formed in the process were analyzed and imaged by SEM and EDS. The degree of graphitization of the C was evaluated by Raman spectroscopy.

6

Cost-effective titania layers over 100 nm thick : effect of annealing on the structural, morphological, and optical properties

51%

Zięba M. , Tyszkiewicz C. , Gondek E. , Wojtasik K. , Nizioł J. , Dorosz D. , Starzyk B. , Szymczak P. , Pakieła W. , Rogoziński R. , Karasiński P.

Opto-Electronics Review

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2023

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tom Vol. 31, No. 4

art. no. e147913

EN

Titania dioxide (TiO₂) layers were synthesized via the acid-catalysed sol-gel route using titania (IV) ethoxide, and then annealed at temperatures varying in the range of 150-700 °C. The research concerned the effect of annealing temperature on the structure of TiO₂ layers, their surface morphology, and their optical properties. Further, X-ray diffractometry, and Raman spectroscopy were used to determine the structure of TiO₂ layers. Scanning electron and atomic force microscopy were used to study the surface morphology of TiO₂ layers. Transmittance, reflectance, absorption edge, and optical homogeneity were investigated by UV-VIS spectrophotometry, while the refractive index and thicknesses of TiO₂ layers were measured using a monochromatic ellipsometer. Chromatic dispersion characteristics of the complex refractive index were determined using spectroscopic ellipsometry. Structural studies have shown that the TiO₂ layers annealed at temperatures up to 300 °C are amorphous, while those annealed at temperatures exceeding 300 °C are polycrystalline containing only anatase nanocrystals with sizes increasing from 6 to 20 nm with the increase of the annealing temperature. Investigations on the surface morphology of TiO₂ layers have shown that the surface roughness increases with the increase in annealing temperature. Spectrophotometric investigations have shown that TiO₂ layers are homogeneous and the width of the indirect optical band gap varies with annealing temperature from 3.53 eV to 3.73 eV.