Умови служби футеровки сталерозливних ковшів і вимоги, пропоновані до вогнетривких матеріалів
In recent decades, domestic and foreign metallurgy has been developing progressive new areas of out-of-furnace processing of steel in ladles (ladle metallurgy) and continuous casting of machines for continuous casting of billets, which provides a high level of steel quality. Bucket metallurgy includ...
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| Date: | 2023 |
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| Main Authors: | , , , |
| Format: | Article |
| Language: | Ukrainian |
| Published: |
Physico-technological Institute of Metals and Alloys
2023
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| Subjects: | |
| Online Access: | https://www.metalsandcasting.com/index.php/mcu/article/view/70 |
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| Journal Title: | Metal and Casting of Ukraine |
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Metal and Casting of Ukraine| Summary: | In recent decades, domestic and foreign metallurgy has been developing progressive new areas of out-of-furnace processing of steel in ladles (ladle metallurgy) and continuous casting of machines for continuous casting of billets, which provides a high level of steel quality. Bucket metallurgy includes methods of purging steel with inert gases, powders, vacuuming, degassing, desulfurization, carbon removal, dephosphorization, deoxidation, and alloying. In addition, the processes of vacuum-oxygen refining, nitric-oxygen decarburization, vacuum-arc remelting, electroslag remelting, circulating vacuum are widely used. All these operations are carried out in special units of complex steel processing.
The introduction of ladle metallurgy turns steel ladles into reactors that serve not only for transporting and casting steel, but also for the development of new technologies, including refining, alloying, deoxidation, degassing and production of high
 
quality steels with specified special properties. In reactor ladles, the service conditions of refractory lining change, the duration of metal in the ladle increases taking into account the time of its secondary out-of-furnace processing, there is a need to increase the steel temperature during release from the steelmaking unit or by heating in the ladle. All this, of course affects the wear of the lining and reduces the stability, so the requirements for the composition, quality of bucket refractories are growing. Taking into account the chemical composition of steels, methods of secondary processing choose refractories and types of linings.
The choice of ladle refractories is dominated by general trends in the use of basic, neutral, oxygen-free and composite materials. More stable periclase, high-alumina refractories and their modifications are especially widely used.
The use of periclase-limestone, limestone-periclase (dolomite) refractories allows to reduce economic costs while increasing wear resistance by 1.5 times. The use of periclase-carbon products in ladles for machines of continuous casting of blanks allows to increase the stability of the lining to 50–100 pours and reduce the specific consumption of refractories to 4–5 kg/t of steel.
The refractories of the new generation include synthesis systems based on oxides, oxide-oxygen-free and oxygen-free materials.
Refractory systems MgO-CaO-ZrO2-Al2O3-C include periclase (MgO), periclase-limestone (MgO-CaO), limestone-periclase (CaO-MgO), periclase-lime-zirconium (MgO-CaO-ZrO2), limestone (CaO), spinel (74 % Al2O3, 23 % СаО), periclase-spinel (MgO-Al2O3), spinelcorundum (Al2O3-MgO-C) with the addition of carbon alloying or without carbon (graphite), periclasecarbon (MgO-C), periclase-spinel-carbon (MgO-Al2O3-C) et al.
In ladle metallurgy, their use is expanding, but given the relatively high cost so far, these refractories are used as additives, bonds in individual structural elements, coatings, coatings, impregnations.
In accordance with the conditions of service to ladle refractories have high requirements for thermophysical properties. Refractories for the working layer of the lining must have high fire resistance temperatures, softening under load, have sufficient strength characteristics at high temperatures. They have to be dense, heat-resistant, slag-retaining, to have the maximum shrinkage, consistency of volume, accuracy of the sizes. Due to the different conditions of service and the many requirements for the choice of bucket supplies are differentiated taking into account the properties of refractories, design features and purpose of the bucket.
Taking into account all the above, a number of measures have been developed in the converter shop of PJSC MK Azovstal, which allowed to increase the performance and stability of steel bucket linings, reduce the cost of refractory materials by 7.7 % and get a significant economic effect. |
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