Browsing by Author "Harvanec, Jakub"

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    Study of local mechanical properties and deformation mechanisms of the soft zone of welded joints of high-strength steels
    (University of Žilina, 2025) Harvanec, Jakub; Mičian, Miloš; Frátrik, Martin
    High-strength steels (HSS) are crucial in the production of lightweight structures. Their welding creates a distinct heterogeneous heat-affected zone (HAZ) in which a softened zone with locally lower mechanical properties forms. This critical zone acts as a weak point, concentrates strain, and can initiate failure, thereby compromising the structural integrity of the welded joint. Detailed understanding of the local behaviour of this zone is insufficiently investigated. Standard tests provide only basic data, which limits the reliability of simulations and the integrity assessment of steel structures. The article deals with the characterization of the local mechanical properties and deformation behaviour of the HAZ softened zone using the DIC (Digital Image Correlation) and nanoindentation techniques. The combined approach enables a comprehensive understanding of the mechanical properties of the HAZ subzones, crucial for assessing the reliability and integrity of welded structures.
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    Vplyv technológie tepelného spracovania na tribologické vlastnosti vybraných oceľových materiálov
    (University of Žilina, 2024) Harvanec, Jakub; Mičian, Miloš; Nový, František
    The heat treatment technology changes all sorts of materials properties. We examined the change of tribological properties of selected powder metallurgy materials and conventional steels, in this article. We used special testing equipment, for measuring the changes of friction coefficient of individual tested materials, before application of the heat treatment and after application of the heat treatment. We tested two types of powder metallurgy steels and two types of conventional steels. The changes in friction coefficient are shown in the table and charts. We used boronising, nitriding and surface hardening as procedures of heat treatment.