FEATURES OF THE CONTINUOUS CASTING OF CORROSION-RESISTANT STEEL

Abstract

The world demand for corrosion-resistant steel has grown nearly 50% in the last decade ‐ from 8 to 13‐13.5 million tons/yr ‐ and it is expected to increase further [1]. If certain assumptions are made, it can be stated that the productio n and consumption of corrosion-resistant steel serves as an index of the industrial development of a country. In connection with this, manufacturing companies are actively engaged in the production and sale of corrosion-resistant steel and in investing in equipment modernization and improving technologies for the manufacture of this product. One element of the production process is continuous casting. Foreign and domestic experience in the production of corrosion-resistant steel shows that the continuous casting of titanium-bearing steel is the most labor-intensive and complex casting operation, based on the requirements that must be met to ensure a quality cast product. In this article, we examine technological aspects of the production of corrosion-resistant st eel. Specific features of corrosion-resistant steel Kh18N10T make it difficult to obtain continuous-cast ingots of this steel that will have a good surface and a minimal number of macrostructural and microstructural defects. In particular, the steel has substantial concentrations of easily oxidized elements (Al, Ti, Cr, Si). Their reaction with carbon, nitrogen, and oxygen dissolved in the metal or present in the atmosphere results in the formation of oxides, nitrides, and carbonitrides that have a high melting point and adversely affect the fluidity of the steel. Ingots of steel Kh18N9-19T can have a defect known as edge porosity or “titanium” porosity, which is related to rotation of the solid skin formed on the surface of the metal in the mold. The defect is usually located about the periphery of the ingot and propagates into it to a depth ranging from 1‐2 to 20‐25 mm.