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Aluminium loss during Ti-Al-X alloy smelting using the VIM Technology

Smalcerz Albert, Blacha L., Łabaj J.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 1

11--17

EN

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.

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Influence of the Power of Various Types of Induction Furnaces on the Shape of the Metal Bath Surface

Smalcerz Albert, Węcki Bartosz, Blacha Leszek

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 3

34--42

EN

The work shows the results of examinations conducted to ascertain the influence of the working power of a vacuum induction crucible furnace (ICF) and a furnace with a cold crucible(CCF), on the surface area of liquid Al-Zn alloy molten within these devices. It was determined that the increase of the value of this parameter causes the increase of the liquid alloys surface area. In the case of smelting alloy inside a crucible furnace the increase of power from 8 to 22 kW causes the increase of liquid alloy surface from 88 to 155 cm2. For a furnace with a cold crucible, the power increase from 70 to 130 kW causes the increase of the alloy surface from 280 to 330,3 cm2. For all power values a larger increase in surface area was observed in crucible furnaces (around two times). In cases of cold crucible furnaces, this increase was around 20%. Additionally, based on the examination results the way in which the surface area of liquid alloy can intensify the undesirable process of zinc fuming away, was discussed. It has been demonstrated that the process of zinc elimination from the examined alloy is more intensive while using a cold crucible induction furnace.

3

Removal of Lead From Blister Copper by Melting in the Induction Vacuum Furnace

Smalcerz A., Blacha L.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 2

84--88

EN

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.