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The manufacturing technology was tested and the quality study of super-thick sheets made of highstrength structural cold-resistant steel AB2R made from large ingots was carried out. Ingots are poured with siphon using modern pouring and heat-insulating mixtures while protecting the metal with argon. The use of the developed technology for casting large ingots together with the use of out-of-furnace refining and metal modification with aluminum and calcium provides a high level of quality of super-thick rolled products.

The quality of rolled product of high-strength low-carbon steel prepared from slabs using an improved reduced heat treatment regime is studied. It is shown that use of this heat treatment regime for slabs of high-strength vessel steel (Cr–4Ni–Mo–V composition), including a high-temperature tempering operation, with a hydrogen content in molten steel not more than 1.8 ppm provides rolled product quality at the level of metal of standard production. The use of the new regime makes it possible to reduce significantly the production cycle duration.

The effect of technology of introducing REM on the composition and shape of nonmetallic inclusions and physicomechanical properties of carbon and low-alloy steels for different purposes is analyzed, and criteria are provided for REM consumption in relation to sulfur and oxygen content within metal, making it possible to determine the optimum REM distribution with which there is an increase in ductility properties, impact energy, and sheet and plate anisotropy properties of the sheet are reduced. Microalloying of carbon and alloy steels and alloys with REM improves corrosion resistance, hot ductility, thermal shock resistance, and other operating properties.

Physical and physicochemical properties are considered for rare-earth elements (metals) and their reaction with oxygen, sulfur, and nonferrous metal admixtures during steel production. Introduction of REMs in optimum amounts makes it possible to modify nonmetallic inclusions both in a liquid condition and during steel crystallization, to refine cast workpiece structure due to inoculation action, and to improve physicomechanical and operating properties of a broad range of steels and alloys. Melt stirring is necessary in order to improve steel purity with respect to nonmetallic inclusions during REM introduction and subsequent steel treatment.

A process is developed for the production of high-strength vessel steel. It includes the application of a microcrystalline REM-containing modifier and an improved regime of preliminary heat treatment of ingots. This process ensures high hot deformability of ingots and a substantial decrease in the time of production of high-strength vessel steel. The quality of the produced steel meets the requirements of the existing technical forms and records.

The characteristics of alloys for the reduction and modification of steel are considered, such as complex composition, low melting point, chemical and structural uniformity, and low susceptibility to oxidation. Attention focuses on alloys containing magnesium, alkaline-earth and rare-earth elements, titanium, and zirconium. The effectiveness of multicomponent alloys with a microcrystalline structure is primarily associated with the action of barium on the liquid steel; barium may be regarded as a universal reducing and modifying agent for steel.

A technology is developed for production of high-strength austenitic nitrogen-containing steel, including melting of intermediate product in a basic arc furnace, ladle vacuum-oxygen decarburization, and furnace ladle treatment. Use of contemporary large metallurgical units and the developed technology makes it possible to assimilate industrial production of high-strength austenitic nitrogen-containing steel with provision of a prescribed chemical composition and product quality corresponding to required specifications.

The theoretical and technological aspects of improving the regime of preliminary heat treatment of forged slabs made of a high-strength vessel steel are analyzed. An improved (short) regime of preliminary heat treatment of forged slabs is developed and tested under industrial conditions. The developed regime is shown to be promising.

The effect of inoculating a high-strength shipbuilding steel with flux-cored wires containing FeCa and FeCa in a complex with rare-earth metals (REMs) on the distribution, composition, and morphology of nonmetallic inclusions is investigated. It is shown that inoculation with both FeCa and FeCa in combination with REMs with the calcium and cerium content of the metal within 0.002–0.003% for each of them allows obtaining a high-strength shipbuilding steel with a low level of contamination by nonmetallic inclusions.

The influence of barium-bearing ferroalloys on the mechanical properties of cast and deformed steel is studied. Such ferroalloys greatly reduce the metal’s content of gases and nonmetallic inclusions, increase the impact strength of steel for railroad castings, and improve the plasticity of high-strength shipbuilding steel.

The effect of top and bottom pouring of large forging ingots on the quality of high-strength shipbuilding steel plate 150 mm thick is studied. It is shown that technology developed for forging billet top pouring in argon at atmospheric pressure and bottom pouring under a slag-forming mix with protection of the metal stream by argon provides a high level of quality for ultrathick shipbuilding steel plate.

Features of extra-furnace refining technology are considered for high-strength shipbuilding steel sheet, with which high metal purity is provided with respect to non-metallic inclusions. It is demonstrated that the maximum ductility of sheet in the Z-direction is achieved due to optimizing the aluminum and calcium content in the steel.

Samples with typical defects were cut from plates to study the scabs metallographically. The macrostructure of the metal at the site of the defect was studied on transverse sections cut from the samples and etched in a hot 50% solution of hydrochloric acid. The microstructure was studied on unetched sections and on sections etched with a 4% alcohol solution of nitric acid. After etching, Oberhoff's reagent was used to determine phosphorus segregation in the base metal and at the site of the defect.