Статті КМТОМ (ІПБТ)
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Browsing Статті КМТОМ (ІПБТ) by Author "Deineko, Leonid M."
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Item Features of the Ferrite-Bainite Structure Low-Alloy Low-Carbon Steel after Heat Hardening and Subsequent Tempering(Prydniprovska State Akademy of Civil Engineering and Architecture, 2021) Deineko, Leonid M.; Borysenko, A. Yu.; Taranenko, A. A.; Zaitseva, T. O.; Romanova, Nataliia SerhiivnaENG: Problem statement. In recent decades, there has been a tendency to increase the mechanical properties of low-carbon, low-alloyed steel plate iron by using controlled rolling or hardening heat treatment of finished steel parts. At the same time, for welded parts, the most suitable is a metal having a ferrite-bainite (or bainite) structure. The work investigated the features of the ferrite-bainite structure of low-carbon and low-alloyed steel 15ХСНД for the production of connecting pipeline parts. Purpose of the article. To establish the laws of formation of a ferritic-bainitic structure in low-carbon low-alloy steels depending on the parameters of heat treatment. Determine the effect of heat treatment parameters on the properties of the connecting parts of pipelines made of these steels. Conclusion. The regularities of the influence of heat treatment parameters on the structure, mechanical properties and topography of fractures of impact samples of 15ХСНД steel with a ferrite-bainitic structure are established.Item Simultaneously Enhancing Strength, Ductility and Corrosion Resistance of a Martensitic Stainless Steel via Substituting Carbon by Nitrogen(Springer, 2023) Li, Fuyang; Tian, Jialong; Li, Huabing; Deineko, Leonid M.; Jiang, ZhouhuaENG: Two martensitic stainless steels of 2Cr12Ni6 type hardened and tempered at 773 K have been studied: the first with 0.2% carbon content and the second with partial replacement of carbon by nitrogen (C0.1N0.1) in the first steel. It is found that the partial substitution of carbon with nitrogen contributed to an increase in ductility and strength of the steel, presumably due to the formation of more dispersive carbonitrides. Meanwhile, the addition of nitrogen suppressed the precipitation of carbonitrides, so that the solid solution strengthening effect of C0.1N0.1 did not decrease significantly after tempering treatment. In addition, the partial replacement of carbon by nitrogen contributed to improved ability against pitting corrosion (PC) in chloride-containing medium (3.5%NaCl at 303 K). The higher resistance to PC of tempered nitrogen-containing steel is apparently due to the lower content of massive carbonitrides, especially the reduced aggregation at grain boundaries. This leads to a lower acidity and aggressiveness of the test solution near the sample surface due to the accumulation of NH4 + ammonium ions in it. As a result of nitrogen addition, exception for Cr 23 C 6 and VC, Cr 2 N and (Cr, V) N type precipitates have also been found in C0.1N0.1 steel and this is consistent with the thermodynamic calculation results. In conclusion, substituting carbon by nitrogen in traditional martensitic stainless steel could realize the simultaneous improvement of multiple properties of martensitic stainless steels. This result provides a promising composition optimization route to develop novel martensitic stainless steels.