Improving Shipbuilding Steel Grade Quality at Stages of Smelting, Secondary Refining, and Continuous Casting

Abstract

This work studied the effect of the amount of additives and the composition of refining slags on the metallurgical of steel grades of the S355G10, S420G2, and S460G2 types. The objects of study were samples of industrial melts after out-of furnace refining of steel with different amounts and nature of additives. Based on the results obtained, the recommended amounts of additives and the composition of the refining slag have been developed, which makes it possible to reduce the metal contamination with non-metallic inclusions.

Structural Anisotropy Parameters’ Effect on the Low-Temperature Impact Strength of Alloy Steels in Rolled Products

“…It is known that the degree of zonal segregation is determined by a combination of several factors, which include the composition of the steel and its metallurgical history [26][27][28]. Metallurgical heredity in the cast state is characterized by dendritic and zonal segregation, which is manifested during the crystallization and solidification of steel, due to various thermo-physical and hydrodynamic conditions for the formation of certain structural zones of the slab.…”

“…This is evidence of the presence of carbon and oxide films in defective samples, which are a metallurgical defect and cause a drop in low-temperature impact strength. Based on the results of X-ray microanalysis destruction surface, it can be argued tha the composition of the film includes Al, Si, C, Na, K. The reason for their formation may be slag-forming mixtures (SFM) used in continuous casting steel, which include these elements [13,16,17].…”

“…When the metal is cooled to the temperature of about 800 °С, the reaction 2{СO}→C + {CO2} actively proceed (Figure 16) with carbon emission to the surface of the microcavities. Based on the results of X-ray microanalysis destruction surface, it can be argued that the composition of the film includes Al, Si, C, Na, K. The reason for their formation may be slag-forming mixtures (SFM) used in continuous casting steel, which include these elements [13,16,17].…”

“…It is known from the work of present-day researchers that segregation heterogeneity in finished rolled products can be manifested in the form of axial central segregation heterogeneity, which is a consequence of axial chemical heterogeneity, as well as the axial discontinuity of a continuously cast billet [15]. The degree of the segregation band development in the structure of rolled products depends both on the concentration of highly segregating elements such as sulfur, phosphorus, carbon, non-ferrous metal impurities, a number of alloying elements, and on the crystallization conditions, as well as the solidification parameters of the continuously cast billet [16,17]. Rolled sheets and coils with a pronounced segregation band are characterized by an increased tendency towards defect formation, including internal delamination with the formation of cracks directed along the interface between the segregation band and the base metal.…”

Titanium Carbide and Vibration Effect on the Structure and Mechanical Properties of Medium-Carbon Alloy Steel

“…The experience of using ultrafine particles is known from the practice of hardening heat-resistant alloys [7] and aluminum alloys [8,9]. There are also positive examples of the use of various ligatures of rare earth metals and alloys based on them being used as modifiers [10]. The analysis of the information shows that the introduction of ultrafine powder modifiers significantly improves the mechanical properties of alloys, including wear resistance.…”