21. Austenite reversion suppression with deep cryogenic treatment : a novel pathway towards 3rd generation advanced high-strength steelsPatricia Jovičević Klug, Matic Klug Jovičević, Lars Thormählen, Jeffrey McCord, Michael Rohwerder, Matjaž Godec, Bojan Podgornik, 2023, original scientific article Keywords: Martensitic stainless steel, deep cryogenic treatment, microstructure, mechanical properties, microstructural transformations, phase transformation Published in DiRROS: 02.02.2024; Views: 153; Downloads: 83 Full text (13,70 MB) This document has many files! More... |
22. Effect of double-step and strain-assisted tempering on properties of medium-carbon steelPavel Salvetr, Andrea Školáková, Jakub Kotous, J. Drahokoupil, Daniel Melzer, Zdeňek Jansa, Črtomir Donik, Aleksandr Gokhman, Zbyšek Nový, 2023, original scientific article Keywords: medium-carbon steel, tempering, strengthening, mechanical properties, microstructure Published in DiRROS: 02.02.2024; Views: 156; Downloads: 75 Full text (9,82 MB) This document has many files! More... |
23. Effect of Cu alloying on mechanical properties of medium-c steel after long-time tempering at 500 °CPavel Salvetr, Aleksandr Gokhman, Milan Svoboda, Črtomir Donik, Ivana Podstranská, Jakub Kotous, Zbyšek Nový, 2023, original scientific article Keywords: long-time tempering, strengthening, Cu precipitate, medium-C steel, mechanical properties Published in DiRROS: 02.02.2024; Views: 200; Downloads: 74 Full text (6,20 MB) This document has many files! More... |
24. Complex interdependency of microstructure, mechanical properties, fatigue resistance, and residual stress of austenitic stainless steels AISI 304LPatricia Jovičević Klug, Matic Klug Jovičević, Michael Rohwerder, Matjaž Godec, Bojan Podgornik, 2023, original scientific article Keywords: stainless steel, AISI 304L, deep cryogenic treatment (DCT), microstructure, mechanical properties, fatigue, residual stress Published in DiRROS: 02.02.2024; Views: 168; Downloads: 82 Full text (5,90 MB) This document has many files! More... |
25. Tribological evaluation of vegetable ▫$oil/MoS_2$▫ nanotube-based lubrication of laser-textured stainless steelMarjetka Conradi, Bojan Podgornik, Maja Remškar, Damjan Klobčar, Aleksandra Kocijan, 2023, original scientific article Abstract: In the present work, the functionalisation of austenitic stainless steel, AISI 316L surfaces via nanosecond Nd:YAG laser texturing in order to modify the surface morphology with crosshatch and dimple patterns is presented. A tribological analysis under lubrication with sunflower and jojoba oil with and without the addition of a solid lubricant, MoS2 nanotubes, was performed. In conjunction with friction/wear response laser-textured surface wettability, oil spreadability and oil retention capacity were also analysed. It was shown that the crosshatch pattern generally exhibited lower friction than the dimple pattern, with the addition of MoS2 nanotubes not having any significant effect on the coefficient of friction under the investigated contact conditions. This was found in addition to the better oil spreadability and oil retention capacity results of the crosshatch-textured surface. Furthermore, texturing reduced the wear of the stainless-steel surfaces but led to an approximately one order of magnitude larger wear rate of the steel counter-body, primarily due to the presence of hard bulges around the textured patterns. Overall, the crosshatch pattern showed better oil retention capacity and lower friction in combination with different vegetable oils, thus making it a promising choice for improving tribological performance in various environmentally friendly applications. Keywords: tribology, stainless steel, vegetable oil lubrication, MoS2 nanotubes Published in DiRROS: 02.02.2024; Views: 129; Downloads: 75 Full text (4,56 MB) This document has many files! More... |
26. Aspects of bending high-borated austenitic stainless steel sheets for interim storage of spent nuclear fuelJosef Odehnal, Tomáš Studecký, Petra Čejková, Ivana Poláková, Martin Rund, Václav Bruná, Petr Martinek, Pavel Francisko, Črtomir Donik, 2023, original scientific article Keywords: interim storage, spent fuel, borated stainless steel, cold working, bending Published in DiRROS: 01.02.2024; Views: 141; Downloads: 66 Full text (10,05 MB) This document has many files! More... |
27. Influence of boron and nitrogen on the machinability, polishability and wear of martensitic stainless steelsMarko Sedlaček, Barbara Šetina, Vesna Žepič Bogataj, Jaka Burja, 2023, original scientific article Keywords: martensitic stainless steel, boron, nitrogen, wear, machinability, polishability Published in DiRROS: 01.02.2024; Views: 148; Downloads: 78 Full text (7,53 MB) This document has many files! More... |
28. LCA and LCC assessment of UHPFRC application for railway steel bridge strengtheningIrina Stipanović, Sandra Škarić Palić, Aljoša Šajna, Martín-Sanz Henar, Eleni Chatzi, 2021, published scientific conference contribution Abstract: Most of the existing railway steel bridges are nowadays older than 70 years, experiencing serious aging and overload problems. Therefore they either need to be replaced or strengthened to fulfil the increased requirements. The main idea of strengthening existing steel bridges is considering the possibility of adding load bearing deck above the main girders without replacing them. In this particular case study, the original steel structure of the 9m long railway bridge was dismantled and transported to the laboratory for the experimental assessment and development of the new rehabilitation method. Based on the assessment results, a strengthening slab was designed using Ultra High Performance Fibre Reinforced Concrete (UHPFRC) formula. In the life cycle analysis, using LCC and LCA models, the comparison of the application of UHPFRC cast in-situ deck is compared to the bridge replacement solution, which was actually selected method by the owner. The executed solution used also a temporary bridge in order to enable continuous traffic, which has caused very high construction costs. In order to compare different options, we have additionally analysed a solution without a temporary bridge, which created three life cycle scenarios. Most important steps during the construction, exploitation and end-of-life stage have been taken into account and integrated into the LCA and LCC models. Finally the environmental, economy and societal impacts of three solutions were compared over the period of 60 years. The rehabilitation option with UHPFRC deck has shown by far the lowest direct and environmental cost while the user delay costs only after the period of 50 years are not the most convenient for users. Superior characteristics of UHPFRC enabled the optimization of the load bearing deck and by that a very low total used quantity of material resulting in minimum direct and indirect costs. Keywords: railway steel bridge, UHPFRC, strengthening, LCA, LCC model Published in DiRROS: 25.01.2024; Views: 167; Downloads: 112 Full text (9,29 MB) This document has many files! More... |
29. Optimizing hot-work tool steel microstructure for enhanced toughnessAnže Bajželj, Tilen Balaško, Barbara Šetina, Jaka Burja, 2024, original scientific article Keywords: hot-work tool steel, austempering, bainitic transformation, lower bainite, impact toughness Published in DiRROS: 24.01.2024; Views: 212; Downloads: 91 Full text (9,12 MB) This document has many files! More... |
30. Use of steel slag for the synthesis of belite-sulfoaluminate clinkerLea Žibret, Martina Cvetković, Maruša Mrak, Mojca Loncnar, Andrej Ipavec, Sabina Dolenec, 2020, published scientific conference contribution Abstract: Belite-sulfoaluminate (BCSA) cements are low-carbon mineral binders, which require low energy consumption and allow the incorporation of various secondary raw materials in the clinker raw meal. In this study two types of unprocessed steel slags, coming from stainless steel production, were incorporated in the BCSA clinkers. The clinker phase composition, clinker reactivity, and the compressive strength of the cement were studied to evaluate the possible use of the slag in BCSA clinkers. The cement clinkers were synthesized by using natural raw materials, white titanogypsum, mill scale, as well as two different steel slags: (i) EAF S slag, which is a by-product of melting the recycled steel scrap in an electric arc furnace, and (ii) la dle slag as a by-product of the processes of secondary metallurgy, in various quantities. Raw mixtures with two different targeted phase compositions varying in belite, calcium sulfoaluminate and ferrite phases were sintered at 1250 °C. Clinker phases were determined by Rietveld quantitative phase analysis, while their distribution, morphology and incorporation of foreign ions in the phases were studied by SEM/EDS analysis. The clinker reactivity was determined by isothermal calorimetry. BCSA cements were prepared by adding titanogypsum. The compressive strength of the cement pastes was determined after 7 days of hydration. The presence of a predicted major clinker phases was confirmed by Rietveld analysis, however periclase was also detected. Microscopy revealed subhedral grains of belite and euhedral grains of calcium sulfoaluminate phases, while ferrite occurred as an interstitial phase. The results showed differences in the microstructure and reactivity of the clinker and cement, which can be attributed to varying amounts of ettringite due to different slag types Keywords: belite-sulfoaluminate cement, cement clinker, steel slags, clinker microstructure, cement reactivity Published in DiRROS: 19.01.2024; Views: 186; Downloads: 82 Full text (18,89 MB) This document has many files! More... |