Кафедра матеріалознавства та термічної обробки металів (ДМетІ)

Permanent URI for this communityhttp://crust.ust.edu.ua/handle/123456789/14633

UK: Кафедра матеріалознавства та термічної обробки металів (Дніпровський металургійний інститут, ДМетІ) EN: Department of Material Science and Heat Treatment of Metals (Dnipro Metallurgical Institute, DMetI)

Browse

Now showing 1 - 3 of 3

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 Serhiivna
ENG: 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.
Modern Technologies for Strengthening Steels for the Manufacture of Protective Elements of Bulletproof Vests. Part 1
(National Science Center, Kharkiv Institute of Physics and Technology, Kharkiv, 2026) Deineko, Leonid M.; Pinchuk, Victoria L.; Panchenko, A. V.
ENG: In the conditions of a full-scale war that is ongoing in Ukraine, the issue of protecting the lives and health of citizens has acquired particular importance. Reliable personal protective equipment, in particular personal protective equipment (PPE) – bulletproof vests, are vital to save lives and minimize the risks of injuries and wounds not only from bullets, but to a greater extent from fragments. The key requirement for the armor plate material is the ability to withstand the action of ammunition of a certain type without penetrating and damaging a person with fragments that can peel off from the opposite plane of the armor plate. Armor steels provide such ballistic resistance with high-strength low-alloy or alloyed grades and the structural state of the metal, which is provided by preliminary and final thermal (or combined) treatment. The specific level of properties of the metal of armor plates already depends on the protection class (for which they are planned), chemical composition and metal processing parameters. The purpose of this article is to study the influence of the chemical composition of steels and the modes of thermal (for a homogeneous state) and chemical-thermal treatments (to obtain a heterogeneous state) on the properties of the steels selected for the study and to choose a rational composition of steels for the manufacture of protective sheets of armor and to develop modern processing modes to ensure 4–5 classes of protection according to DSTU 8782:2018, which is one of the key ones in Ukraine in this area. Based on the results of theoretical and experimental research, parameters of the technology of heat treatment with volumetric strengthening of protective elements of body armor are proposed, using chromium-nickel-molybdenum-vanadium steel as an example to obtain bulletproof effect up to class 5 of protection in the conditions of operation of body armor.
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, Zhouhua
ENG: 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.