SU366630A1 - - Google Patents

Description

INSTALLATION FOR ELECTROSLAG FIBER

12

The invention relates to the field of electrometallurgy and can be applied to electroslag remelting of metals, in particular steel.

Installations for electroslag remelting of metals are known; remelting electrodes in them are supplied from three-phase current-frequency converters of a network frequency to a single-phase current of low frequency, which, for example, can be performed on thyristors. In this case, if a single remelting electrode is used in low and medium power installations, in a high power installation several electrodes or groups of electrodes are used, each of which is powered by its own converter.

A disadvantage of multi-electrode installations is that the distribution of currents and powers in the slag bath cannot be controlled.

The purpose of the invention is to increase the quality of remelting.

This is achieved by the fact that the installation for electroslag remelting of metals is equipped with a phase shift regulator of single-phase voltages of chalk-sdu groups of electrodes and a bottom plate associated with thyristor converters.

FIG. 1 shows the scheme of the installation described; in fig. 2 - time diagrams

METALS

voltages (pos. a) with time diagrams of currents (pos. b).

The installation is powered by a three-phase network RST, to which the step-down transformers 3 are connected to the wires / via switches 2, to the outputs of which through the phase 4 and zero 5 wires are connected thyristor converters 6 equipped with a phase shift regulator 7. Wires 8 converters are connected with remelted electrodes 9. Melting is carried out in a water-cooled mold 10 under a layer of slag 11. As a result of remelting, liquid metal 12 is formed, which solidifies into an ingot 13 mounted on the bottom plate 14. Last wire / 5 is connected to converters 6

During remelting, part of the current supplied to the electrodes 9 through wires 8 flows through the slag from the electrode to the electrode (current / l), and the other part through the ingot, bottom plate 14 and wires 15 (current IB) Ratio of currents IE and / in depends on the phase shift of the voltages Ui and t / 2 between the electrodes and the bottom plate, which can be set by any means using the controller 7.

If the phases of the voltages Ui and U U coincide, then the voltage UF. between electrodes 9 is zero, the current IE is also zero, and the current / and the current rhven / i and / 2 electrodes 9:

If the voltages Hi and U are shifted by the half period, then the voltage UE between the electrodes at each time instant is twice the voltage C / ток current / in is zero, and the current IE is the sum of the currents / i and / 2.

If the phase shift between the voltages And and t / 2 is less than half the period, then at those moments when the direction of the voltages Ol and U are different, the voltage UE and current / are different from zero, and the current / in is zero. At the same points in time, when the directions of the voltages and and and coincide, the voltage VE and the current IE are equal to zero, and the current / in equals the sum of the currents / 1 and / 2.

Thus, the phase shift between the voltages U and (Jz can be changed. The values of the currents / d and / in. On the other hand, the greater the current IB, the deeper the bath of liquid metal 12. With the pulsed nature of the current / in the resulting electrodynamic effects cause the melting metal to break into small droplets, which are especially well cleaned in the slag.

I am unable to work on the described installation.

R sg

With two, and with a large number of electrodes or groups of electrodes. In addition, it is possible to create an electromagnetic rotating field that has a rotating effect on the slag and metal baths. This improves the quality of the remelting.

Subject invention

The installation for electroslag ireilava .L1 metals, containing a water-cooled mold, a bottom plate, several groups of remelted electrodes and the same number of thyristor converters of three-phase current of the network frequency into a single-phase low frequency current, the output terminals of which are connected to the bottom plate and to the electrode ground, which differs that, in order to improve the quality of the non-alloy, it is equipped with a phase shift regulator of single-phase voltages between a group of electrodes and a bottom plate connected to the indicated scale Reversal transducers.