International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Modern armor steels are essential in safeguarding military and civilian assets from ballistic threats. This paper provides a comprehensive classification of contemporary armor steels, examining their material properties, including hardness, impact resistance, and the influence of chemical composition, particularly carbon equivalent (CE), on their performance. The classification considers chemical composition, alloying elements, and mechanical properties, with a focus on their ballistic effectiveness and suitability for various armored platforms. Additionally, the paper delves into the historical evolution of armor steel, tracing its origins from early military applications to the sophisticated alloys used today. It also highlights the importance of MIL-DTL specifications in establishing a standardized language for armor steel grades, ensuring uniformity in quality and performance across the defense sector. Furthermore, the paper discusses the role of heat treatment procedures, such as quenching and tempering, in influencing the microstructure and mechanical properties of armor steels, directly affecting their resistance to penetration and impact. Through a review of armor steel classifications, historical context, and their technological advancements, this paper offers valuable insights into the ongoing efforts to improve the performance and reliability of armored materials.

Due to technological particularities of low carbon low alloy API 5L X80 steels producing they have strong texture and its inhomogeneity on plate thickness. Charpy impact tests at ambient and negative temperatures and investigation of texture of samples of API 5L X80 steel were performed. By the method of X-ray structural analysis DPF, IPF and ODF were obtained. Texture components and their volume fraction were determined. It was shown that correlation between volume fractions of main texture components, misoriented grains fraction and DBTT exists. As a result analysis of texture parameters allowed characterization of effect of texture on cold resistance of low carbon low alloy API 5L X80 steel.

Investigation of low carbon microalloyed API 5L X80 steels for electric-welded pipes applied in building of metallic structures of different complexity. Problems of weldability of these steels and effect of technological and structural factors on mechanical properties of weld seams have been considered. Also mechanical characteristics at cyclic loading of the steels are considered.