JPH0820827A - Electro-slag remelting method - Google Patents

Abstract

PURPOSE:To improve the working efficiency at the initial stage of remelting and to uniformize the characteristic of an obtd. steel ingot by preheating the tip part of a consumable electrode at the initial stage of the remelting by using an electro-slag remelting method. CONSTITUTION:At the time of producing the steel ingot having excellent cleanliness and uniform characteristic by using the electro-slag remelting method, the steel-made consumable electrode 1 as the raw material is fit to a turnable arm 5 for hanging down the electrode and then, an induction heating coil 8 is fit to the tip part of the electrode 1, and the electric current is conducted to the coil 8 to heat the tip part of the electrode 1 by the induction current. Melting rate of the tip part of the electrode 1 becomes large at the initial stage of the remelting refining of the consumable electrode by this heating, and the whole melting time of the electrode 1 can be shortened, and the steel ingot having excellent uniformity is obtd. by remelting under the excellent working efficiency.

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 from now on is at room temperature, the actual dissolution rate at the beginning of the remelting is slower than the remelting rate in the subsequent portions. This is because after the start of remelting, the heat of conduction from the remelting portion and the consumable electrode 1 are gradually shortened to gradually increase the remelting rate due to the power factor improving action. Therefore, the work efficiency at the beginning of remelting is inferior to the work efficiency of the subsequent remelting, and it is not preferable in order to obtain the steel ingot 10 as uniform as possible.

[0003]

DISCLOSURE OF THE INVENTION The present invention makes the work efficiency at the start of re-dissolution close to the work efficiency of subsequent re-dissolution by increasing the dissolution rate at the initial stage of the start of re-dissolution, and it is possible to obtain a property as uniform as possible. It tries to get closer to the steel ingot.

[0004]

[Means for Solving the Problems] By increasing the dissolution rate at the beginning of remelting, the work efficiency at the beginning of remelting can be brought closer to the work efficiency of the subsequent remelting, and a steel ingot with as uniform a property as possible To solve the problem, it is possible to solve the problem by preheating the vicinity of the tip of the remelting start side of the consumable electrode at room temperature.

[0005]

By preheating the vicinity of the remelting start side tip of the consumable electrode in the normal 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.

[0006]

Embodiment An embodiment will be described below with reference to the drawings. FIG. 2 shows an embodiment in which the consumable electrode 1 used in the prior art shown in FIG. 1 is attached to a swivel electrode suspension arm 5, and then the consumable electrode 1 is preheated below the consumable electrode 1, that is, near the electrode tip on the remelting start side. Is shown. In this embodiment, a method of preheating the vicinity of the tip of the electrode 1 on the remelting start side by the induction heating coil 8 is shown, but there is no problem even if another heating method such as flame heating or furnace heating is used. Absent. After the main preheating is performed, the electrode suspension arm 5 is swung to set in the copper water-cooled crucible 2 which is prepared for melting in advance, and remelting is started.

[0007]

The present invention in one embodiment shown in FIG. 2 under the condition that the current and voltage during the subsequent remelting are kept constant except for 1 hour immediately after the start of remelting in FIG. The effect of is compared with the prior art. The vertical axis represents the amount of redissolution per unit time, the horizontal axis represents the elapsed time from the start of redissolution, and the solid line 1
1 shows the redissolved amount per unit time according to the present invention, and the dotted line 12 shows the redissolved amount per unit time according to the prior art.

That is, according to the method of the present invention, it becomes possible to increase the amount of redissolved per unit time by about 2 kg from the start of redissolution until about 4 hours have elapsed, and this increased amount is gradually reduced. The total re-dissolution time, which required 15 hours in the conventional technique, can be shortened by 1 hour. As a result, it is possible to improve the production efficiency by about 7% and to improve the slow melting rate at the initial stage of the start of remelting, which is aimed at obtaining a steel ingot 10 having a property as uniform as possible. The slag remelting method made it possible to further the original purpose.

[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 embodiment in which the vicinity of the tip of the consumable electrode on the remelting start side is preheated.

FIG. 3 is a characteristic diagram 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 ... Steel ingot, 11, 12 ... Redissolved amount.

Claims (1)

[Claims] 1. An electroslag remelting method, characterized in that in the electroslag remelting method, the vicinity of the tip of a consumable electrode corresponding to the initial portion of melting is preheated to improve the dissolution rate at the beginning of remelting.