JPH0835019A - Electro-slag remelting method - Google Patents

Abstract

PURPOSE:To improve a working efficiency and to uniformize the characteristic of the obtd. steel ingot by heating a consumable electrode and executing an electro-slag remelting operation to increase the melting speed. CONSTITUTION:A copper-made water-cooling crucible 2 is arranged at the upper part of a copper-made water-cooling surface plate 3 on a surface plate pedestal. While advancing the consumable electrode 1 into this crucible 2 through a hanging-down beam 5, the electric discharge is executed between the consumable electrode and molten slag 6, and the consumable electrode is melted from the tip part thereof and the molten metal pool 7 is formed to obtain the remelted steel ingot 10. In the electro-slag remelting method, the consumable electrode 1 is heated by an induction heating coil 8 fitted to the tip part thereof. By this constitution, the neighborhood of tip part of the consumable electrode under room temp. condition is heated at the starting time of remelting, and further, the heating is continued on the way of remelting, too, and the melting speed is increased at the same time of starting the remelting. Further, the remelted steel ingot having uniform characteristic can be obtd. by executing the controlling beating together with cont rolling the voltage and the current for discharging.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electroslag remelting method.

[0002]

2. Description of the Related Art It is a known fact that the electroslag remelting method is used as a means for obtaining a steel ingot having excellent cleanliness and uniform properties, and an outline of the prior art is shown in FIG. . This method is shown by an electroslag remelting method in which the copper water-cooled crucible 2 moves (the copper water-cooled crucible 2 moves upward and the consumable electrode 1 moves downward as the remelting progresses). Since the consumable electrode 1 to be redissolved is at room temperature, the dissolution rate at the start of remelting is actually slower than the remelting rate at the subsequent parts, and the work efficiency at the start of remelting is later. Inferior to redissolving work efficiency. Further, after the start of remelting, the remelting rate gradually increases due to conduction heat from the remelting portion and the power factor improvement due to the consumable electrode 1 becoming shorter. For this reason,
It was extremely difficult to control the dissolution rate only by the current and voltage. These are not preferable in terms of work efficiency and also in order to obtain the steel ingot 10 that is as uniform as possible.

[0003]

The present invention improves work efficiency by increasing the dissolution rate at the start of re-dissolution and thereafter.
Moreover, it is intended to approach a steel ingot having a property as uniform as possible.

[0004]

[Means for Solving the Problems] By increasing the melting rate at the start of remelting, the work efficiency at the start of remelting can be made closer to the work efficiency of subsequent remelting, and can also be made as close as possible to a steel ingot of uniform properties. Can be solved by heating the vicinity of the tip of the consumable electrode on the side of remelting at room temperature and heating the consumable electrode even during the subsequent remelting.

[0005]

By heating the vicinity of the remelting start side tip of the consumable electrode in the room temperature state, the time required for the temperature near the remelting start side tip of the consumable electrode to rise in the conventional case can be shortened. After the start of remelting, the temperature near this tip also has the effect of accelerating the conduction to the subsequent parts of the consumable electrode. Furthermore, by heating the consumable electrode even during remelting, it has the effect of increasing the remelting rate thereafter. This improves the work efficiency, and the control of the remelting rate can be controlled by heating the consumable electrode without relying only on the current and voltage, so that the steel ingot with a property as uniform as possible is to be obtained. It brings about the effect of approaching the purpose of the electroslag remelting method.

[0006]

Embodiment An embodiment will be described below with reference to the drawings.

FIG. 2 shows an embodiment for heating the consumable electrode 1 used in the prior art of FIG. In this embodiment, a method of heating with the induction heating coil 8 is shown, but there is no problem even if another heating method, for example, a method of flame heating is used. In this embodiment, the induction heating coil 8 is used.
The heating method is applied when the dissolution rate reaches an excessively high rate, or when it is expected that it will reach an excessively high rate, this heating is stopped and the dissolution rate becomes too low. This is because it is easy to restart the heating when the temperature is reached or when it is expected that the temperature will drop too low.

[0008]

The effect of the present invention is shown in FIG. 3, except for the first hour before the start of re-dissolution, under the condition that the current and voltage at the time of subsequent re-dissolution remain constant in FIG. The effect of the invention will be shown in comparison with the prior art. The vertical axis represents the redissolved amount per unit time, the horizontal axis represents the elapsed time from the start of redissolution, the solid line 10 represents the redissolved amount per unit time according to the present invention, and the dotted line 11 represents the conventional unit per unit time. The redissolved amount of each is shown. In this example, the heating of the consumable electrode was stopped 2 hours after the start of remelting, the heating was restarted 3 hours later, and the heating was stopped 5.5 hours later.

That is, according to the method of the present invention, the amount of redissolved per unit time can be greatly increased to about 6 to 1 kg from the prior art until about 11 hours after the start of redissolution, and the prior art It was possible to shorten the total re-dissolution time, which required 15 hours, by 3 hours. As a result, the production efficiency can be improved by about 20%, the slow melting rate at the beginning of the intended remelting can be improved, and the ingot of the electroslag remelting method which is intended to obtain a steel ingot with a property as uniform as possible is desired. It has become possible to greatly advance the purpose, and it became extremely easy to control the current and voltage in the past to keep the remelting rate constant.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a conventional technique of an electroslag remelting method.

FIG. 2 is an explanatory diagram of an example of heating a consumable electrode.

FIG. 3 is a graph comparing the amount of redissolution per unit time between the present invention and the prior art under the condition that the current and voltage are kept constant.

[Explanation of symbols]

1 ... Consumable electrode, 2 ... Copper water-cooled crucible, 3 ... Copper water-cooled surface plate, 4 ... Surface plate base, 5 ... Electrode suspension arm, 6 ... Molten slag, 7 ... Molten pool, 8 ... Induction heating coil, 9 ... Cooling Water, 10 ... Redissolved amount.

Claims (1)

[Claims] 1. An electroslag remelting method comprising heating a consumable electrode in the electroslag remelting method.