Titanium alloys belonging to the group of modern metallic materials used in many industries, including the aerospace industries. Induction crucible vacuum furnaces and induction furnaces with cold crucible are most commonly used for their smelting. When operating these devices, one can deal with an adverse phenomenon of decrease in the content of alloy elements that are characterized by higher equilibrium vapour pressure than the matrix metal or titanium, in the metal bath. In the paper, results of the study on aluminium evaporation from the Ti-Al-Nb, Ti-Al-V and Ti-Al alloys (max 6.2 % wt.) during smelting in a vacuum induction melting (VIM) furnace are presented. The experiments were performed at 10 to 1000 Pa for 1973 K and 2023 K. A significant degree of aluminium loss has been demonstrated during the analysed process. The values of relative aluminium loss for all the alloys ranged from 4 % to 25 %. Lowering the pressure in the melting system from 1000 Pa to 10 Pa resulted in increased values of aluminium evaporation flux from 4.82⋅10-5 to 0.000327 g⋅cm-2⋅s-1 for 1973 K and from 9.28⋅10-5 to 0.000344 g⋅cm-2⋅s-1 for 2023 K. The analysis of the results obtained took into account the value of the actual surface of the liquid metal. In the case of melting metals in an induction furnace, this surface depends on the value of power emitted in the charge. At greater power, we observe a significant increase in the bath surface due to the formation of a meniscus.
The usage of the reduced pressure in the processes of smelting and refining of metal alloys allow to remove not only the gases dissolved in the metal bath, but also the impurities having a higher vapour pressure than the matrix metal. Blister copper produced in flash furnace contains many impurities such as lead, bismuth and arsenic. Some of them must be removed from molten metals, because of their deleterious effects on copper electrical properties. When the smelting process is carried out in the induction vacuum furnaces, the above-mentioned phenomenon is being intensified, one or another mixing of bath and increase in the surface area of mass exchange (liquid metal surface). The latter results from the formation of a meniscus being an effect of the electromagnetic field influence on the liquid metal. In the work, the results of refining blister copper in terms of removing lead from it, are presented. The experiments were carried out in the induction crucible vacuum furnace at temperatures of 1473 and 1523 K, and operating pressures in a range of 8 - 533 Pa.
W artykule zaprezentowano wyniki analizy wpływu mocy indukcyjnego pieca próżniowego VIM ISM 2-200 na pole powierzchni ciekłego metalu. W pierwszym etapie badań rejestrowano obraz z wykorzystaniem kamery termowizyjnej podczas nagrzewania metalu dla mocy roboczych pieca wynoszących 70, 100 oraz 130 kW. W drugim etapie badań wyznaczano pola powierzchni powstałych menisków. Przykładowe wyniki omówiono i zestawiono w artykule.
EN
This paper presents the results of the analysis of the influence of the induction vacuum furnace power VIM ISM 2-200 on the surface area of liquid metal. In the first stage of the research, the image was recorded using a thermo vision camera during metal heating for the furnace power 70 kW, 100 kW and 130 kW. In the second stage of the study, was calculated liquid metal surface areas. The exemplary results are discussed and summarized in the article.
W pracy dokonano oceny wpływu parametrów procesu wytapiania stali w laboratoryjnym indukcyjnym piecu próżniowym na jakość otrzymanego wlewka. Wśród parametrów procesu został uwzględniony dobór wsadu zapewniający otrzymanie stali o pożądanym składzie chemicznym oraz warunki termodynamiczne procesu i czas wytapiania. Ocena jakości otrzymanego wlewka polegała na porównaniu planowanego składu chemicznego z rzeczywistym, pomiarze stężenia składników stali na przekroju wlewka wzdłuż jego osi symetrii, a także identyfikacji wielkości powstałej jamy skurczowej. Możliwości laboratoryjnego indukcyjnego pieca próżniowego pozwalają na wytwarzanie nowych lub modyfikacje istniejących stopów żelaza połączone ze stabilizacją składu chemicznego w wąskich granicach.
EN
The work has evaluated the impact of steelmaking process parameters in laboratory vacuum induction furnace on the ingot quality. Among the process parameters it has been included to ensure the selection of the batch to obtain a steel having a desired chemical composition and thermodynamic conditions of the process and time of melting. Evaluation of ingot quality is made base on a comparison of the planed and real chemical composition of the steel ingot in cross-section along its axis of symmetry and identification the size of the shrinkage cavity. Capabilities of VIM furnace allow the manufacture of a new or modifications of existing iron alloys combined with the stabilization of the chemical composition within narrow limits.
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