Synticom-Original Metallic Charge for the Electric Furnace Steelmaking of High-Quality Steels

摘要

Cast iron and scrap are the main charge materials used to make high-quality steel. Cast iron is character-ized as an original charge material with a well-known chemical composition and a low content of nonferrous metal impurities. Cast iron is the most widely used charge material for making high-quality steel intended for the manufacture of autobody sheets, pipes, rails, wheels, metallic cord, wire rods, spring steel, and so on. However, cast iron is a rather expensive charge material and its use is restricted to the technological conditions of steelmaking. The lowest amount of (liquid and solid) cast iron is used for electric furnace steelmaking (up to 40%). The amount of (liquid and solid) cast iron is maximal for the converter method of steelmaking (75-80% or more). A significant fraction of liquid cast iron makes it possible to make steels with a low total content of nonferrous metal impurities (down to 0.10-0.13%) in a converter. According to the European Economic Community of the United Nations Organization (L.N. Shevelev, Restructuring of Ferrous Metallurgy—Action of New Technologies (Working Group on Steel, Geneva, 1997)), the fraction of making such steels in converter steelmaking increased from 86.6% in 1990 to 97.3% in 2000 and the fraction of conventional carbon steel decreased from 13.4 to 2.7%, respectively. In con-trast, in electric furnace steelmaking, the fraction of high-quality steel in this period decreased from 49.4% in 1990 to 30.5% in 2000, whereas the fraction of con-ventional carbon steel increased from 50.6 to 69.5%, respectively. This decrease in the fraction of high-quality steel in electric furnace steelmaking is mainly explained by a sharp decrease in using high-quality steel scrap (lump electric furnace scrap with a low con-tent of nonferrous metal impurities) due to an increase in the fraction of continuous casting of steel.