Prospects for the development of steel production

Abstract

The duplex steelmaking shop at the Chusovoi Metallurgical Plant began operation in 1946. The shop includes a 400-ton mixer, three 20-ton Bessemer converters, and two 270-ton open-hearth (OH) furnaces. The shop specializes in refining naturally alloyed vanadium pig iron in the converters to produce vanadium slag and a carbon-bearing semifinished product which is subsequently transformed into steel in the OH furnaces and into a commercial semifinished product.The vanadium pig iron is sent to the mixing department in 50-ton ladles. The pig is then transferred to a 25-ton hot-metal-car ladle which has a ladle-tilting mechanism. The car transports the hot metal to the converter department, where it is poured into the Bessemer converters. Before the pouring operation, sinter or scale is charged into the furnace by an 80/20-ton overhead travelling crane.The metal is bottom-blown by compressed air with a pressure of 0.20--0.22 MPa (2.0-2.2 psig) at a rate of 500 m3/min under normal conditions. The duration of the heat is 15-16 min, including 5-6 min of blowing. The converter has a basic (magnesite) lining except for the bottom, which has an acid (dinas) lining. These linings have a maximum life of 3000 and 400 heats, respectively.The resulting semifinished product, which contains 3.0-3.5% C and 0.04---0.07 V, is poured into a 50-ton steel-car ladle (two heats are poured into one ladle) and sent to the OH furnaces.The OH department has two OH furnaces. The furnaces are provided with evaporative cooling and are fired by natural gas (70%) and carbureted fuel oil (30%). The outgoing heat is used in waste-heat boilers. The furnaces are equipped with a system that completely automates the thermal regime. Each OH furnace is charged by two crane-type changing machines with a capacity of 5/20 tons. The liquid semifinished product is charged in 50-ton ladles with the use of an 80/20-ton crane. The steel is tapped into two 130-ton steel-pouring ladles.The pouring bay is serviced by three 180/50/15-ton cranes. The liquid metal is bottom-poured into closed-bottom ingot molds placed on 12 carts (16 molds on each cart, with another 8 molds located on a tray); each ingot weighs 1890 kg. The compositions used for refining are prepared in two bays. During 1988 the duplex shop made 395,500 tons of steel, including 182,000 tons of ordinary grades, 15,500 tons of quality grades, 4,300 tons of free-cutting steel, 61,800 tons of chromium steel, 23,700 tons of silicon steel, 92,800 tons of manganese steel, and 15,400 tons of low-alloy steel.Solving the problem of attaining high technical-economic indices will require a complete reconstruction of the shop. The metallurgical complex should include highly efficient and economical conversion of vanadium pig iron, with the recovery of 95% of the vanadium in the slag.World steelmaking practice shows that converter steelmaking is characterized by a relatively high level of technological sophistication, making it possible to produce steel from pig irons of a wide range of compositions. This is very imp...