Thermodynamic studies of CuO-Fe2O3-Al exotermic mixture with a combine oxidant in self-shielding flux cored wires
Abstract
Trembach B. A., Grin A. G., Miloserdov P. A., Trembach I. A. Thermodynamic studies of CuO-Fe2O3-Al exotermic mixture with a combine oxidant in self-shielding flux cored wires // Herald of the DSEA. – 2019. – № 2 (46). – P. 41–46.
An upcoming trend in the development of self-shielding flux cored wires is the development of surfacing materials with exothermic mixtures, in order to increase melting parameters. However, the introduction of a significant amount of exothermic mixture may be undesirable in obtaining the desired composition of the deposited metal, due to the reduction of the components of the oxidizer and its subsequent pass into the deposited metal. Use the exothermic mixture with the combined oxidizer of the CuO-Fe2O3-Al system as the components of the exothermic mixture of the stock of the flux cored wire, which makes it possible to control the deposited metal composition to a greater degree. Computer-aided calculation of the adiabatic combustion temperature of the combined exothermic mixture under investigation was carried out using the ISMAN-THERMO program. Studies have shown that an increase of graphite content (from 6 % to 9 %) in the flux cored wire leads to a significant decrease of the adiabatic temperature of combustion of an exothermic mixture with a combined oxidizer, which is caused by an activation of stock melting. It was determined that the introduction of graphite reduces the adiabatic temperature of combustion and can eliminate the possibility of copper boiling, as evidenced by the decrease in the content of the latter in the gas phase. For a composition with a smaller amount of graphite (6 % C), carbon passes into the metal phase, only in the form of carbides. With a larger amount of graphite (9 % C) in the composition of the stock, it is possible to provide passing of free carbon into the melting zone. Thermodynamic calculations of a complex multicomponent exothermic mixture, CuO-Fe2O3-Al, with a combined oxidizer of the system have shown that an increase of CuO content leads to an increase in the metal phase and a decrease in the oxide phase, for the cases under consideration.
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