Investigation of the Influence of Electro-Impulse Current on Manganiferous Liquid-Alloy

Abstract

he article shows that for improving the quality of castings, more and more often, technical solutions are used related to the influence of electric current on the melt during its crystallization. The positive results of such a modification are improved processes of heat and mass transfer and structuring. However, these results only concern the electrical treatment of non-ferrous metals and alloys, as well as some castings. The influence of the electric current limits on the degree of modification of manganese-containing steels during their crystallization in the foundry, as well as on the physical and mechanical properties of the casting requires careful research that would be close to real conditions. The authors compared the macro and microstructures of steel 35GL doped with manganese and modified during crystallization in the foundry form of the electro-impulse current with different current parameters: intensity, duration of impulses, frequency, squinting. It has been established that the modification of an alternating polarity with an electric pulse current of more than 10–3 s, a frequency of 5–33 Hz, a force of 30–40 A, a vacuum of 5–24, at a voltage in the power line of 180–240 V provides a reduction in structural inhomogeneity (the crystallite of the metal base and manganese carbides are reduced respectively from 280 to 82–85 microns and from 6.7 to 0.3–0.5 microns). These structural changes lead to a significant increase in the basic mechanical properties of cast structural steel 35GL: strength limits – 9%, impact strength – 21%, hardness (HB) – 6%.