1. Thermal-mechanical sensory properties of hot-air welded textile transmission linesSimona Jevšnik, Li Yi, Junyan Hu, Han Xiao, Wu Xinxing, Anthony Primentas, 2016, original scientific article Abstract: Hot air welding technology is one of the new promising techniques for integrating conductive yarns on or into fabrics, besides weaving, knitting, printing, coating or inserting conductive yarns by the sewing and/or embroidery processes. A new issue related to the introduction of hot air welding technology for making e-textile transmission lines, i.e., the mechanical-thermal sensory properties of hot air welded e-textile transmission lines, is investigated in this study. Fabric Touch Tester (FTT) was used to evaluate thermal, compressive and bending properties of hot air welded transmission lines. The results show that the bending of welded fabric increased after hot air welding in both warp and weft directions. Furthermore, the maximum thermal flux and thermal conductivity of welded specimens decreased in comparison to the substrate fabric.
Keywords: textile transmission lines, hot-air welding, fabric touch tester, conductive yarns, e-textile transmission lines, thermal properties
Published in DKUM: 01.09.2017; Views: 1017; Downloads: 410
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2. Application of semantic technology for calculation of welding time in the development of new productsAmbrož Stropnik, Tomaž Vuherer, Ivan Samardžić, Milan Zorman, 2017, original scientific article Abstract: Determining the time of execution is very important in the early stages of each project (e.g. making offers, design phase etc.), especially in the stage of planning. This paper presents our approach to estimating the welding time for the purposes of planning the manufacturing processes. The approach is based on the knowledge of welding experts from the Nieros metal d.o.o. company and standards of welding (international and internal). An expert system was developed based on semantic web technologies for calculating the welding time in the product design phase and it is strongly integrated with the main ERP system of the Nieros metal d.o.o. company. Test results are presented at the end of this article.
Keywords: expert systems, new product development, ontology, welding of steels
Published in DKUM: 23.08.2017; Views: 922; Downloads: 377
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3. Influence of kinematic factors of friction stir welding on the characteristics of welded joints of forged plates made of EN AW 7049 A aluminium alloyMilenko Perović, Sebastian Baloš, Dražan Kozak, Darko Bajić, Tomaž Vuherer, 2017, original scientific article Abstract: In this paper, the influence of rotation speed and welding speed on the impact strength, microstructure and cross section micro hardness of FSW welded joints of Al-Zn-Mg-Cu high strength aluminium alloy is studied. Rotation speed was varied from 750 min−1 to 850 min−1 and welding speed from 60 mm/min to 80 mm/min. It was found that the energy of crack propagation is up to three times higher than the energy of crack initiation. This ratio was found by testing the Charpy notched specimens taken from left and right from the weld centre, 4 mm from the notch in a direction opposite to a direction of welding. Micro hardness distribution in the nugget does not show large dissipation of value regardless if the measuring point is in the upper or lower section of the nugget. Weld microstructure characteristics and zones are clearly defined at the basis of grain size and material flow.
Keywords: dynamic recrystallization, friction stir welding, impact strength, micro hardness distribution
Published in DKUM: 12.07.2017; Views: 1193; Downloads: 357
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4. The influence of electric arc activation on the speed of heating and the structure of metal in weldsOleksandr Savytsky, Mychailo Savytsky, Darko Bajić, Yuriy Shkrabalyuk, Tomaž Vuherer, 2016, original scientific article Abstract: This paper presents the results of a research related to the impact of electric arc activation onto drive welding energy and metal weld heating speed. It is confirmed that ATIG and AMIG methods, depending on metal thickness, single pass weldability and chemical composition of activating flux, enable the reduction of welding energy by 2-6 times when compared to conventional welding methods. Additionally, these procedures create conditions to increase metal weld heating speed up to 1,500-5,500 °C/s-1. Steel which can be rapidly heated, allows for a hardened structure to form (with carbon content up to 0.4%), together with a released martensitic structure or a mixture of bainitic-martensitic structures. Results of the research of effectiveness of ATIG and AMIG welding showed that increase in the penetration capability of electric arc, which increases welding productivity, is the visible side of ATIG and AMIG welding capabilities.
Keywords: arc welding, active flux, penetration, heating speed, driving energy
Published in DKUM: 07.07.2017; Views: 993; Downloads: 339
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5. Numerical analysis of temperature field during hardfacing process and comparison with experimental resultsVukić Lazić, Ivana Ivanović, Aleksandar Sedmak, Rebeka Rudolf, Mirjana Lazić, Zoran Radaković, 2014, original scientific article Abstract: The three-dimensional transient nonlinear thermal analysis of the hard facing process is performed by using the finite element method. The simulations were executed on the open source Salome platform using the open source finite element solver Code Aster. The Gaussian double ellipsoid was selected in order to enable greater possibilities for the calculation of the moving heat source. The numerical results were compared with available experimental results.
Keywords: welding simulations, numerical analysis, thermal analysis, simulations, transient heat conduction, moving heat source
Published in DKUM: 07.07.2017; Views: 1130; Downloads: 370
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7. The microstructure and properties of materials at the fusion lineVladimir Gliha, 2005, original scientific article Abstract: In this paper, the formation of the HAZ that is caused by the thermal effects of welding is investigated from the theoretical and experimental points of view. Samples of the material found at the fusion line were prepared by simulating the thermal regimes that occur during welding. A number of CCT diagrams that are valid for the conditions during welding were designed, and the hardness and impact-toughness of the samples were measured. This information was then related to the results of metallographic examinations. The maximum temperature and the cooling rate of the applied thermal cycles were found to be decisive in terms of the properties of HAZ.
Keywords: welding, HAZ, thermal cycle, cooling rate, fusion line
Published in DKUM: 03.07.2017; Views: 1935; Downloads: 106
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9. Influence of vibrations on residual stresses distribution in welded jointsIvan Samardžić, Tomaž Vuherer, Dejan Marić, Pejo Konjatić, 2015, original scientific article Abstract: This paper presents research experience related to implementation of vibrations on residual stress relief with the equipment for treatment by vibration method. The paper provides explanation of effects achieved by vibration method when implemented during welding, and elaborates advantages and disadvantages of that method applied after welding process. In order to present effects of vibration on solid structures, there was experimental analysis performed and compared with heat treatment.
Keywords: welding, vibrations, residual stress, heat treatment
Published in DKUM: 03.07.2017; Views: 934; Downloads: 117
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