TŽ Annual Report 2008 in pdf, 7.5 MB - Třinecké železárny

3.Characteristics of the Production PlantsSteel Production in Třinecké železárny Includes the Following Facilities:In the Coke-Chemical Production plant, the production of coke for the needs of the company’s blast furnaces takes place. Two cokeovenbatteries of Koppers design heated by blended or coking gas work with ramming operation. They are equipped with the facility forwet quenching of coke. The coke gas is desulphurised and supplied to the gas networks of Třinecké železárny for subsequent utilisation.Numerous coke chemical products, especially crude coking tar, benzyl, and ammonium sulphate are produced in the consecutivechemical section.The Iron and Steel Production plant comprises: • production of hot iron; and • steel production.Sinter is the basic metal-bearing raw material for the production of hot iron. It is produced in two sintering plants; each equippedwith two sintering belts. In 2007 and 2008, the renovation of electrostatic separators at sinter plant No.1 took place which significantlyreduced the amount of air pollution. The input material of the sintering plants consists of the powdery iron ores, dolomite, lime,pulverised coke, and reverse charging material resulting from production processes.The pig iron production itself takes place in two blast furnaces with bell-free throats equipped with automated control of furnaceoperation. Hot iron is transported to the converter plant in torpedo cars.More than 98 percent of the Třinec steel is produced in the BOF converter plant based on the processing of hot iron with oxygen. Theplant is equipped with top ladle metallurgy facilities, which enable chemical and temperature homogenisation, alloying, preheating, andvacuum degassing of steel. Converter steel is mostly cast at two continuous casting machines; approximately 5 percent of steel is teemedinto ingots, especially the special steel grades. Continuous casting machine No. 1 is of a five-strand design, with the possibility of castingrectangular blooms of 300 x 350 mm and circular blooms of diameters 320, 410, and 525 mm. The eight-strand continuous castingmachine No. 2 enables the casting of square billets with sides of 150 mm. The automatic control system controls the whole converterprocess including the gas cleaning station. The small EAF steel plant producing special steel grades is also a part of the steel productionsection.The metallurgical cycle is concluded by rolling mills, which are the most complex manufacturing units. They consist of the rolling millof blooms and heavy sections, rolling mill of wire rod and light sections in Třinec, and the universal strip mill in Bohumín.The semis are delivered for further processing that ensures an increase in added value to: Sochorová válcovna TŽ located in Kladno,Válcovna trub TŽ located in Ostrava-Vítkovice and VÚHŽ in Dobrá.According to technology, the Rolling Mill of Blooms and Heavy Profiles is divided into two production lines: • blooming mill andreversing mill; and • medium section mill.The continuously cast semis and ingots are rolled at the blooming mill into slabs and blocks, and then at the reversing mill into billets,heavy profiles, special profiles for railway accessories and rails. The medium section mill produces round bars, flat bars, sections forrailway accessories, parabolic springs, and mine rails.The Rolling Mill of Wire Rod and Light Section plant consists of: • continuous light section mill; and • continuous wire rod mill.The product portfolio produced at the continuous light section mill includes round bars and coils, flat bars, hexagons, rebar, and angles.The mill was largely modernised; one of the results of the modernisation was the expansion of the product mix by special bar qualityproducts. A substantial part of the output of the light section as well as wire rod mill is processed at the finalising facilities enablingheat treatment, peeling, drawing, or the combination of those operations based on customer specifications including the inspection ofsurface and internal defects.4