JPS6229087A - Electromagnetic desulphurizer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention is a method for electromagnetically stirring molten metal and a desulfurizing agent
-) 1'1% 1L Yamakokijohon Atsuki Suzubi Jofu Shogotsuji is related.

``Conventional technology'' Cubola is widely used in iron foundries as a means of obtaining molten metal, but coke is used as fuel for cubela, so it is difficult to produce molten metal.

- Molten metal melted using Bora contains a high concentration of sulfur. On the other hand, demand for spheroidal graphite cast iron as high quality cast iron,
Although production is increasing more and more, when using Cubola molten metal, graphite spheroidization by adding a spheroidizing agent is not successful due to the sulfur content, and for this reason, the production of spheroidal graphite cast iron using Cubola molten metal is In general, a desulfurization step is provided before adding the spheroidizing agent. This desulfurization step is a step in which a powdery desulfurization agent is added to the molten metal and desulfurization is carried out through a chemical reaction, and calcium carbide, calcium oxide, etc. are used as the desulfurization agent. In addition, in the desulfurization step, it is necessary to add a desulfurization agent to the molten metal and to further stir it to promote the reaction, and the porous plug method, gas innoection method, etc. are generally used as the stirring method. However, with these stirring methods, the temperature of the molten metal decreases significantly due to stirring, so it is necessary to raise the temperature of the molten metal after desulfurization, and a temperature raising furnace (for example, a groove-type induction furnace) must be separately installed to raise the temperature. However, especially in small-scale production factories, the cost ratio of installing a heating furnace becomes large, which is a problem.

Therefore, in order to solve the above-mentioned problems, the present applicant first developed an electromagnetic desulfurization device that can raise the temperature and stir at the same time. Fig. 3 (a) is a cross-sectional view showing the configuration of this electromagnetic desulfurization device. FIG. 3(B) is a view taken along the line A--A shown in FIG. 3(A). In these figures, 1 is a crucible whose horizontal cross section is of the type shown in the same figure (B), and 2 is this crucible I.
This is a cylindrical communication path that communicates with the bottom 1a of the holder and extends vertically upward.

The crucible 1 and the communication path 2 are each formed using a refractory material 3 inside a cylindrical coil furnace material 11 around which a coil 5 is wound. In this case, the coil 5 is connected to the lower end 2 of the communication path 2.
a and the bottom 1a of the crucible 1 at a sufficient distance above. Reference numeral 6 indicates a yoke arranged radially around the outer circumference of the coil 5, which forms a magnetic path outside the coil 5, shields leakage magnetic flux from the coil 5, and is a steel material (not shown) that constitutes the outer wall of the device. ) to prevent heat generation due to eddy currents. Moreover, this coil 5 is formed of a hollow steel pipe,
During operation, forced water cooling is performed by flowing water into the hollow part. 7 is a cupola melt field that is continuously supplied from the cupola;
8 is a desulfurizing agent whose main component is carnoum carbide.

In the above-described configuration, when an alternating current is supplied to the coil 5, a flow of molten metal as shown by the arrow in the figure occurs in the crucible 1, similar to an induction furnace, etc., and at the same time, a flow of molten metal in the crucible due to an eddy current occurs. A fever occurs.

In this way, the molten metal in the crucible is stirred, desulfurized, heated, and the desulfurized molten metal is heated. & l O is communication path 2 and discharge port I
5 and is discharged to the outside. In this case, since the coil 5 is provided at a sufficient distance above the lower end 2a of the communication path 2 and the bottom 1a of the crucible 1, stirring and desulfurization of the molten metal in the crucible are performed in a single part of the crucible 1. Therefore,
The flow of the desulfurizing agent 8 and slag into the communicating path 2 is small, and the desulfurizing agent 8 and slag do not harden in the communicating path 2 and block the communicating path 2.

"The problem that the invention attempts to solve" By the way, in the electromagnetic desulfurization device described above, the communication path 2
Although it is possible to reduce the amount of desulfurization agent 8 and slag flowing into the tank, there are still the following drawbacks. ■ When receiving the Cubola melt 7 from the Cubola and starting the operation of the electromagnetic desulfurization equipment, if the level of the molten metal poured into the crucible 1 does not reach near the center of the coil 5, the coil 5 When electricity is applied, no heat generation occurs in the molten metal due to eddy current, and during this time the temperature of the molten metal decreases, and there is a risk that the molten metal will solidify in the communication passage 2. This is particularly a problem when receiving molten metal that is tapped at a relatively low temperature.

■A cylindrical casting block called a start block is placed in a crucible.
When trying to obtain a seed hot water by placing it inside the crucible and melting it, the coil 5 is located above the start block inside the crucible, so this start block Top tithe, minus nerme
Ryu) I can't do anything other than Rinkiffl.

This invention was made in view of the above-mentioned circumstances, and when starting the operation of the electromagnetic desulfurization equipment by receiving molten metal from the cubera, the molten metal is poured into the bottom of the crucible before the inside of the crucible is filled with molten metal. This reduces the temperature of the molten metal and prevents the molten metal from solidifying in the communication path.
Another object of the present invention is to provide an electromagnetic desulfurization device capable of obtaining a seed melt by melting a casting lump called a start block placed on the bottom of a crucible.

"Means for Solving the Problem" This invention divides the induction coil provided on the outer periphery of the crucible into two parts, upper and lower, so that the lower end of the lower induction coil is at approximately the same height as the bottom of the crucible. The device is characterized in that it is provided with a switching means for switching and supplying power to the upper or lower induction coil.

``Operation'' At the start of operation, power is supplied to the lower induction coil, and then, when the inside of the crucible is filled with molten metal, power is supplied to the upper induction coil to draw down the molten metal in the crucible. Stir, desulfurize, and raise temperature.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention, and parts corresponding to those in FIG. 3(A) are given the same reference numerals, and their explanations will be omitted.

In this figure, the difference from the conventional electromagnetic desulfurization apparatus shown in FIG.
The lower induction coil 20b is divided vertically into two parts a and a lower induction coil 20b, and the lower induction coil 20b is arranged so that its lower end is approximately at the same height as the bottom surface 1a of the crucible 1. Further, as shown in FIG. 2, an upper terminal 21a is provided at the upper end of the upper induction coil 20a, and a common terminal 21a is provided at the point where the lower end of the upper induction coil 20a and the upper end of the lower induction coil 20b are connected.
1b, and a lower terminal 21c is provided at the lower end of the lower induction coil 20b. A selector switch 22 is provided on each of the three upper induction coils for supplying an N source to either the upper induction coil 20a or the lower induction coil 20b.

In the above configuration, when desulfurizing the cubera molten metal 7, the changeover switch 22 is operated at the start of operation to supply power to the lower induction coil 20b. In this state, the molten metal poured from the cupola into the crucible 1 is heated to ambient temperature, and the desulfurization agent 8
Add the required amount to pre-desulfurize. Next, when the crucible l is filled with molten metal, the changeover switch 22 is operated,
This time, power is supplied to the upper induction coil 20a. From then on,
Stirring, desulfurization, and temperature raising are performed continuously as in the conventional method.

On the other hand, even if a start block is placed on the bottom surface t'b of the crucible I and the start block is melted at the start of operation, power is first applied to the lower induction coil 20b as in the case described above. supply, dissolve the start block, then cue +'I! UhX et al. Cubola melt
When Jj7 is poured and the crucible l is filled with molten metal,
Operate the changeover switch 22, and now the upper induction coil 2
Supply power to 0a.

Thereafter, stirring, desulfurization, and temperature raising are performed continuously in the same manner as before.

Here, after the time when the crucible l is filled with molten metal, power is supplied to the upper induction coil 20a to perform stirring, desulfurization,
The reason why the temperature is raised is that the upper induction coil 20a is provided at a sufficient distance above the lower end 2a of the communication path 2 and the bottom 1a of the crucible 1, so that stirring of the molten metal and
This is to perform desulfurization in the upper part of the crucible 1 and to reduce the flow of the desulfurization agent 8 and slag into the communication path 2.

"Effects of the Invention" As explained above, according to the present invention, the induction coil is divided into upper and lower halves, and the lower end of the lower induction coil is arranged at approximately the same height as the bottom of the crucible, and the upper Alternatively, since a switching means is provided to switch and supply power to the lower induction coil, when pouring molten metal from the cupola into the crucible and starting the operation of the electromagnetic desulfurization equipment, the period until the inside of the crucible is filled with molten metal is The temperature of the molten metal poured into the bottom of the crucible is low T1. It is possible to prevent this from occurring, and it is also possible to obtain a seed bath by melting the starter block placed on the bottom of the crucible.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of one embodiment of this +jl,
FIG. 2 is a sectional view showing a schematic configuration of the induction coil 20 shown in FIG. 1, FIG. ) is the same figure (a)
It is an AA line arrow view shown in FIG. l...crucible, pot, 1b...bottom, 2...
...Communication path, 20...Induction coil, 20a...
... Upper induction coil, 20b... Lower induction coil, 22... Changeover switch.

Claims (1)

[Claims] A crucible to which molten metal is continuously supplied, and a communication passage communicating with the bottom of the crucible and having an opening above the bottom to discharge the desulfurized molten metal to the outside are each wound in a cylindrical shape. In an electromagnetic desulfurization device that is installed inside an induction coil and simultaneously raises the temperature and stirs the molten metal in the crucible by electromagnetic induction, the induction coil is divided into upper and lower halves, and the lower end of the lower induction coil is An electromagnetic desulfurization device, characterized in that it is arranged at approximately the same height as the bottom of a crucible, and is provided with a switching means for switching and supplying power to an upper or lower induction coil.