Technology Directorate

Róbert MÓGER

Chief Metallurgist

+36 (25) 584 180

+36 (25) 583 800

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Róbert JÓZSA

Technology Chief Engineer

+36 (25) 582 852

+36 (25) 584 772

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Steel is a flexible, high-strength iron alloy with good formability. Its characteristics can be changed to a great extent by different processes, for instance its hardness can be increased to almost that of diamond. Several ways of its production is known, one of the most widespread ways all over the world is the basic-oxygen steel-making process also applied by ISD DUNAFERR, which is an oxidizing melting process. During this materials are charged into a large basic oxygen furnace (converter) having refractory lining. The main charge materials, hot metal and solid steel scrap are put into the converter together with fluxing agents. Then oxygen is blown in through the upper hole, the water-cooled injection lance, as an effect of which oxidizing melting takes place at a high temperature, the final product of which is crude steel. During blowing main part of the carbon content of charge burns out, silicon content is totally oxidized together with a part of manganese and phosphorus content. Contacting the oxygen in air, CO-gas developed during oxidation burns to be CO and is transferred into the wet scrubber. Heat content of BOF gas is used for steam production. Oxides of silicon, manganese and phosphorus become components of the slag developed by blowing process. Sulphur content of charge is bound in the slag in the form of CaS. Inactive gas (argon or nitrogen) flushing is possible through the flushing blocks at converter bottom during the whole manufacturing process.

Steel charge is deoxidized and alloyed during tapping, and then its target chemical composition is set at the ladle metallurgical station. Primary slag is entrapped during tapping. The inclusion content of steel is decreased by argon flushing during the ladle metallurgical treatment, the inclusion content can be changed by injecting Ca-cored wires. Oxygen level and temperature of the charge can be controlled.

Basic oxygen steel-making process was started in Dunai Vasmű (Danube Ironworks) in August 1981. Two basic oxygen furnaces with the capacity of 135 tonnes each operate in the Converter Plant of the Steelworks of ISD DUNAFERR Zrt., production is performed in 2/1 operating mode, alternately. Production in 2/2 operating mode is possible during the period of converter change. Annual capacity: 1.6 million tons of steel.