The year 1993 was a breakthrough for Železiarne Podbrezová – a new electric arc furnace was put into operation. The company became self-sufficient in the production of steel blooms for the needs of the tube rolling mill. The electric arc furnace – often called the heart of the factory, has been beating continuously for three decades.
One of the largest investment in the company history was preceded by years of preparation. The issue of the production efficiency and ecology was already addressed in the year 1969, in the study of the factory development. The Siemens-Martin furnaces and two electric furnaces of that time were outdated and morally worn out.
Smelting in SM furnices lasted six hours and in electric arc furnaces four hours. The intended electric arc furnace (EAF) was supposed to be faster, cheaper and thanks to the dust exhaust system also more environmentally friendly. The EAF furnace was built on the area of the former profile rolling mill. Together with the continuous casting facility already operating since 1982 it meant that a new era began in Železiarne Podbrezová.
In May 1990 the foundation stone of the EAF furnace was laid. In September of the same year, the profile rolling mill was shut down, and immediately after that, the construction of the foundations for the new electric steel mill began. On November 1, 1992, the Siemens-Martin and electric arc furnaces were also shut down. All the necessary works related to the installation and also the finishing process have started. In February 1993, everything was ready to start the new furnace. During the construction, the production of the company was not stopped, con cast steel blooms for the rolling mill were purchased from Třinecké Železárny – Moravia Steel.
The first heat was successfully tapped on February 24, 1993, six hours after the first charging basket was loaded. The ceremonial commissioning took place on March 19.
The most modern of its kind in Central Europe
The EAF was one of the most modern of its kind in Central Europe. In the beginning, one heat took six hours, today it takes about an hour. Its greatest advantages are the automatic regulation of electrodes, the loading conveyor belts, cooling of panels, and also the automated control of the furnace and extraction of fumes produced during smelting. Today, the operators have an overview of all processes that take place in the smelting process. The furnace has a „dog-house“, which is the most important safety element, which dampens noise and at the same time prevents flue gases from spreading into the air.
Part of the construction of the new electric steel plant was also the construction of a ladle furnace (LF), which serves as a reactor for metallurgical operations. EAF produces raw steel, and thanks to the LF furnace, we can produce better quality steel from it.
Constant innovation is essential for both production and the environment
Many innovations have been implemented during these thirty years that contributed to environmental protection and at the same time contribute to product quality and improvement of input material consumption. Innovations and modernization are in line with the company priorities. One of the biggest innovations was the purchase of a replacement the furnace hearth, to make production efficient, since production shutdown was inevitable during the repair of the hearth lining. Another big investment was the installation of bottom blowing elements at the furnace hearth for mixing steel in order to shorten the smelting time.
In 2007, the oxy-fuel burners were installed to help melt at the cold spots and to speed up steel production. The permanent camera helps to identify the slag leakage during tapping. Shortly thereafter, the installation of new equipment for taking a sample and measuring the temperature of the steel took place.
Ten years ago, there was built a new, more efficient equipment for EAF and LF dedusting, which includes heat recovery. The residual heat is used to heat the company offices, the lawn of the football stadium and the swimming pool in the village Podbrezová. The aim of the last investment into the electrode regulation system, which controls of the arc furnace energy-transfer process is to ensure the application of a scheduled power profile and increase safety of the EAF operators.
The EAF is an integral part of the entire joint-stock company. It ensures the smoothness and sufficient efficiency of production and keeps up with modern equipment through constant innovations.
Interesting facts about EAF
• in one hour, the furnace can smelt 60 tons of steel scrap. The Euro trailer – truck capacity is 20 tons.
• the temperature of the melting process reaches 1 620 degrees Celsius,
• EAF consumes as much energy per one minute as a normal household consumes per app. two months,
• with an annual production of 370 thousand tons of steel blooms, it would be possible connect the village Podbrezová and Brussels with a continuous line. The distance between them is 1430 kilometres.
• the higher number of heats was tapped in October 2021, when 25 heats were tapped out in one day. The ordinary production is 21 heats a day.
• by the end of 2022, nine million tons of steel has been produced, which represents distance of 28 391 km of blooms of square cross section 205 mm (the size that is produced most frequently). Did you know that distance between North and South Pole is 13 832 km.
Article written by: Podbrezovan